Taking water and drains a floor up looks like a horribly expensive project. And you'd lose bedroom space. So work with what's already there. The house looks finished well from what I can see on the photos (might be merely esthetic, but still a reason not to hack into it too much). So I've focussed on the extension only (and an extra doorway, so the bathroom is right under the stairs).

Tear it down and rebuild. It looks like the only space that hasn't had some tlc. The grey line is where the old extension ended, so I've added about one metre. And proper rooflights, no plastic. And yes, if the roof height allows, bring up the floor, a few csm lower is good, personally I would not like a full step down.

I guess fire regulations won't allow to bring the kitchen into Rec2, because of the stairs, plus a extra hallway would take up too much space.. And I merely copied the back wall, but some french doors would be nice, of course.

thank you Rinq, how much would it cost to add an ensuite either to the first or loft?

for the changes you made on the ground floor toliet, do we need planning permission? and can you give us a rough estimate on cost on the new roof and moving the toliet?

thanks!
Dani

I have got no idea about costs. And to remove and enlarge an extension I bet you'l need permission.

If you want a bathroom on the first floor, it'll cost you bedroom 3 and to make up for the lost bedroom (and have a window) you'd have to split bed 2 in half, which would leave you with two 200cm-ish wide rooms.

But I can tell you, getting a soil pipe all the way up in a mid terrace, would require a thick pipe to go somewhere (not sure where it would go, as we run pipes internally in the Netherlands and I've seen plenty external in the UK).