Need help planning extension

[Clinkyclunk]

I’m now in the position that I have decided that I want to stay put and extend. I want to extend to the rear by approx 5 metres the entire width of the property. The kitchen and dining room current set up does not work, kitchen is too small, not enough worktops and the dining room is dark and cold so we never use it. We can put sun tunnels in the dining area to brighten it up so the room will receive light. The utility is more a lean too so will be demolished. My wish list is kitchen diner, with a small area for snug/sofa. A pantry (small actual room) and a separate utility room. And if possible a sort of office area that could be semi closed off when needed. Chat GPT has let me down and kept suggesting altering the rest of the house. Any ideas, even radical ones. Current floorplan attached. I don’t actually believe we need masses more space, just more clever use as the dining room is a dead zone.

Is it detached, semi or terraced?
I'd potentially turn the current kitchen into an office and have part of it as a walk in pantry for the kitchen. If its detached or has access outside on that side, depending on the size, I'd split with a wall in the current kitchen to make 1/2 office and 1/2 utility with an access door outside.

Extent out by the 5m and open the current wall out from the dining area to make an L shaped kitchen/diner.

Thanks. It is detached but access on the right hand side is restricted so to put an external door there would not lead to the front or back garden easily. But splitting up the current kitchen is a good idea. The less walls to knock down the better.

If you extend, even with the sun tubes, won't you end up with a very dark bit where the current kitchen and dinning room are?

How much work top do you want and how would it be configured in an ideal world?

Why is the current dining room so dark? Is there scope to add more windows?

Is that the only bathroom? Could you move the washing machine and dryer upstairs into a cupboard to give more space in the kitchen?

There are double doors in the dining room but it’s north facing, only direct sunlight in the summer months really. I think sun tunnels would make a massive difference, but maybe not enough? There is a bathroom upstairs also, but would want to keep the downstairs bathroom.

Worktop at the moment is minimal due to tall cabinets, sink and hob taking up most space. I probably have less than 1m length of useable worktop in the whole kitchen.

Can you pit a window to the left of the dining room? Im advising that's west facing? Possibly the front of the house? Or do you enter at the dide?

I'd add a window there, knock down wall between kitchen and finer and then put a peninsula from back wall where the current dividing wall is. That will add more counter top and light.