Please post photos or drawings of what you want.

Crosswater's Totti range looks similar and has various options which might suit you. I have a similar bath and have used a bath filler which combines with the overflow and then have hot and cold panel valves mounted on the corner near the wall on the curved end of the bath. The advantage of this is that the plumbing is accessible by taking the bath panel off, should you wish to replace the valves etc. There isn't a Totti panel valve but as these are low profile I think you could get away with using a round panel valve.

The fact that your plot is not a rectangle is a good thing. It will mean that you have take a more creative view to designing it which is what all small gardens need! A scaled plan is the best way to design any space but this one in particular will really need it. Look up how to survey it accurately and make a scaled plan. Do not put it on squared paper but on the biggest scale you are able to manage. Then play around! Cut out pieces of paper to represent a good sized seating area, a shed etc. and play with where they can go and what shape they are. If that isn't really working for you then commission a professional garden designer! We can't all be a master of everything! Have fun!

Do not despair, there is a lot you can do to make your garden more secluded with new fencing and clever planting. Is this your only garden? Can I ask whether there is any covenant preventing you from having a taller fence? If not, then can I suggest a 5’ solid fence all round, with a gate. Most dogs will easily jump over your current fence and I’m sure you want to keep your dog safe. If a solid fence is not allowed, then a tall picket fence will do the job, or add taller panels to your current fence as in the second pic. I think a pergola in one corner will give you some more privacy, and you can plant climbers on it for even more privacy (first pic). You can buy them as a flat pack or get a carpenter to make and build one for you. You can add comfy seating, and a doggy bed, under it so you can enjoy your garden on warm days. Now for the planting. I think tall shrubs will create a secret garden effect which will drown out traffic noise and visitor noise! Things like evergreens Viburnum tinus, Ceanothus, Photinia and Choisya ternata Sundance. They can be the bones of your garden. Then add shrubs that are deciduous but add colour in the spring and summer, things like Shrub Roses, Hibiscus, dwarf Lilac, Cotinus and Climbers like Clematis, Star Jasmine, Honeysuckle and climbing roses. These need a wall or trellis or an obelisk to climb up. I can see you have some planting already which is great. The final addition to the planting is perennial flowers and bulbs, but the planting above will create a cosy garden, if you don’t want more planting. Here’s a few pics to inspire you and hopefully reduce your despair! 😊