This is a practical use of a garage to make more space for the rest of your home. Worth considering extra windows, roof windows and external doors for more natural light and access. You also need to level off any floor step downs into the garage with new flooring infill / insulation and concrete. New beams above knock through openings as well. You will need to insulate the walls, floor and roof. You may not need Planning Permission but you will need Building Regulations approval.

Here is one we did a few years ago, used full height strip windows.
https://www.ikonografik.co.uk/garage-conversion-open-plan-kitchen-diner

Hope your project goes well.

This is a great space and you can do so much with it. Make sure you get the ergonomics right when it comes to the layout of the kitchen and this is my speciality. If you look at my bio, it may give you an idea of how I can help get this right for you and your family.

@Ikonografik Design Ltd Thanks for your reply - what a transformation! Lighting is something I’m concerned about as we won’t be able to insert skylights as we have our bedroom above the garage and as we’re not intending to change the front of the garage at all it’s going to be a challenge!

@daniel jay thanks -will take a look at your bio.

Thanks @jonathan. Definitely something to think about.

Our neighbour has done just that. Taken the end of the garage on a linked detached 3 bed house. What a transformation. Nothing above, so very straigjtforward. But they now have the current want, a large kitchen diner. Unfortunately my house is different Design so no can do.

I think you can do all sorts. I do like Jonathan's plan, however, the back of the house is narrow, and thus putting the table against the wall in the middle, may not be ideal for you. Leaving the whole area as a dining area may be preferential.

I would also question the need to move the downstairs toilet, although it does mean that you don't need a door to the utility in the kitchen. However, I think if you leave the toilet where it is, you can still have a super kitchen, put a door at the end to the Utility, and have a better Utility.

Just a word to the wise. If you make a portion of the garage just storage and you have an up and over door, you may need to change it as it will no longer have the room required to go backwards.

I don't know what the access is to your back garden, and since you will almost certainly need to change the garage door, you may like access straight the way through from the garage to the kitchen.

Thus, you could do two things:-

Or go one step further, and remove the wall to the lounge as many people these days like fully open plan.

There are of course other things you may wish to consider, mainly that, instead of having storage in the garage you could possibly have a shed in the garden and use the garage for a smaller Utility and then a study too, giving you a second reception room, which for some is very handy. The access to the Utility and Study would then be through where the toilet is, so that would then move.

So carrying on from what Math ( my husband, officially retired as of today ), said yesterday about another reception:- If you move the Utility door back to the Hallway, you get a larger kitchen area, plus the possibility of the new small second reception / study. This is often essential in a larger house as the kids / teens or adults need their own space.

I personally think this gives the best all round use of space. Really opens up the house and creates a large usable space for everyone.