You need some earth to plant in. You could do it all in pots and planters but in the ground is better and less demanding on the maintenance front. You'll be removing the raised decking but may be replacing the pergola above it, shading the area probably too much for effective planting. Put something else such as seating or table and chairs there for now. The rest of the ground is currently covered in bricks and concrete apart from the barbeque area, which is decking. From what you've said that decking is in decent condition. So now we go to work. I'm setting this work out in sections as a DIY project which could be done stage by stage over any period of time, or periods of time with gaps between, that you choose. I would extend the period of my plan if progress is slow, speed it up if progress is better than anticipated. My plan would start with removing the weeds and dried out plants from the raised beds, both the brick walled and the wooden walled ones. They would be planted with what I want to put there after the soil had been seriously refreshed by mixing in a good amount of fresh compost. Something like three or four inches depth of compost mixed with the top four or five inches depth of soil in the raised bed. My next priority would be to create more growing space. To do that I would remove quite a lot of the bricks from the ground, clean them off as well as I could and store them for now. Some will probably break up, and those would be dumped. The good ones can be used as temporary access paths and pot stands, which will be moved around throughout the following stages. Lots of compost would be added to the newly revealed soil and that is where the next stage of planting would occur. The concrete next. We need to know how thick it is and that will be easy to see at the previous stage with a few bricks removed. Very thick? That's a tough job. Two inches thick? An inch? Less? The thinner the easier. A few whacks with a heavy hammer should break a thin layer up. If it is too thick for that you will need to hire somebody with the effective machinery for the job. I can't see the access in the pix so cannot guide you on what machinery. There is nothing broken up concrete can be used for so it has to go. The revealed earth needs to be revived in the same way as the rest was before planting takes place. We have ended up with bare earth, maybe some bricks left in the ground but otherwise just what we've planted and the loosely laid bricks. Where do you want your path now it's to become a more permanent feature? Don't forget access to the raised beds so you can tend the plants. Where do you want your potted plants? The path and the bases for the pots can now be made stable by putting the bricks back into the ground. I prefer them on their sides but that is up to you. Flat as they are now, on their sides, or a mixture, perhaps side on for the paving and flat as pot supports? I would experiment a little if I hadn't used bricks this way before. No way is right or wrong. It is all down to personal preference. Any bricks still in the ground from the beginning can now be either taken out and used in the plan or perhaps a few have happily ended up just where they're needed. So there is a way forward with very little spending involved. Seeds are mostly very cheap. Plants are cheaper than other materials, labour or professional services. You will swear a lot, sweat a lot and have lots of fun. You will also learn a great deal. If you do end up still feeling you need help you will understand exactly how to brief the professional you appoint.

If the patio area is currently a water trap you need to put drainage in whatever else you do. You also need to think about what is going to be required for the extension and what goes around it. There is very little point spending money now only to abandon what you do and have to spend entirely anew. The manhole near to the downpipe is an obvious target for a ground drainage pipe. Is that manhole going to move next year? If so, run the pipe to where it is going and bend it from there to where it is now, or use an elbow and an extra bit of pipe. At the other end you could simply have holes in the pipe. Or you could construct a French drain as a more permanent solution, which would cost not very much more at all. Is the base for the extension going to be raised so the floors are level? Or sunk to where the land level is outside the kitchen? If lowered, ensure your new drainage pipe will not be above the surface when that happens. If the whole ground area is to be lowered, say with steps to the current entrance, make you new drainage system deeper to accommodate your plan. As you are in Somerset and with only the seasons to add shadow, put the patio where you want it. Unless you really feel like sitting outside in winter. As a temporary covering, gravel, bark chip or woodchip would fit the bill for just a year. But as the current patio is raised so you can step straight out of your door, why remove it? Just take it up for long enough to get the drainage in then put it back. You have the materials in place and there will be less small bits to be trodden into the house. Wait for the extension and do a complete job of it then.

@lisamarie1000 it looks like you've got quite a blank canvas to work with there but as well as giving lots of opportunities it can also be quite daunting if you don't know where to start. As a starting point I would look at where the sun falls in the garden as this can be important for growing vegetables and the greenhouse which need to be in as much sun as possible. Draw a plan to scale of the garden and use cut out shapes to represent the different areas (growing area, play area, sitting area etc.). You can place these on the plan and move them around until you get a layout that you are happy with. The size of the shapes needs to be big enough to represent what their use is. You can also base this on the dimensions of the house such as location of windows and doors. Try to avoid pushing everything to the edges as this can just draw attention to the boundaries and make the space feel small. Think about how you would move through the garden to get to the different areas. If you are going to have a path through, it will be more interesting if this isn't just a straight line down the middle. By making the route through have changes in direction you can add focal points (such as the apple tree) and make the garden seem bigger. If space is tight consider growing vegetables mixed in with ornamental plants so that the garden doesn't look like an allotment. Finally think about using screening with tall plants or trellis at various points so that you don't see the whole garden at once. This can also make the garden seem more interesting and enticing.

Prune in March. Prune about one third to two thirds off down to an outward facing bud. However, Geoff Hamilton, an amazing garden presenter who is no longer with us, did an experiment. He pruned one lot of roses the conventional way above, and the other half was brutally cut back with a hedge trimmer! Both methods did the job and the roses grew exactly the same! Don’t prune now, as the new resulting shoots can get killed by frost and the plant will suffer, wait until the spring.