Sorry - bit of an odd question, I couldn't find much on google about leaks from walls.
Basically where our conservatory meets the exterior wall of the house there is now a small gap. Water is getting in and the exterior wall of house/interior wall of conservatory is getting damp, as well as the other side of that wall (the kitchen)
I don't know who built the conservatory but I would guess it was a big company as it's a standard design and seems in otherwise good condition.
I think it is literally just the seal where the window meets the wall. But obviously I would like a second opinion, but not sure who best to contact. Is it a roofer type job or a builder type job, or a window repair company job?!
By housebuilding standards, conservatories are cheap and shoddy.
I would recommend lead flashing, which is mortared into a slot cut between the bricks just above where the conservatory roof meets it.
If you look at some older houses, you will see lead flashing hs been used to prevent water getting betweem roofs and things they meet.
A competent roofer, or an old plumber*, will know how to do it. Some builders might know how, but be careful, because it is a job needing both care and skill. The material is moderately expensive compared to cheap rubbish other materials.
Under no circumstances accept anyone who offers to glue or nail plastic, bitumen or aluminium to the joint.
Specify that you want lead flashing and not flashband.
*plumber means a person who works with lead. This used to include pipes when they were made of lead. Older plumbers will have learned flashing and the lead parts of roofing during their apprenticeships. Young plumbers probably only know about pipes.
in that case I expect your conservatory is moving away from the house. Take some photos of the gap, with a ruler held there, and some more in six months. Do not try to fix them rigidly together because it will break. Lead is not much good for true vertical joints because it will move under gravity. There is a way of doing it with multiple small overlappping flaps.
Are you on a clay soil?
A sliding component like a wooden post, fixed to the house but tight to the conservatory wall, would fill the gap until the conservatory has moved the thickness of the post. Hopefully this will take quite a long time. Check that rainwater is being run to drains and there is no water getting into the ground around or under the conservatory, e.g. from leaking or missing gutters.