-
Hm, are there limits?
No because our was for a glass box that must have been about one metre square!
Should we have done it for the tiny porch we added?
I don't know mainly because IANAL. When we sold we needed a deed of variation of a lease plan, so that wouldn't be needed for a freehold house. This Land Registry response suggests you don't need to do it at all for a freehold house, but again IANAL...
https://customerhelp.landregistry.gov.uk/forums/general-info-and-guidance/3a4aedf7-906a-ed11-a81b-6045bdcf8811?page=1Yet another reason I would never own anything but a simple freehold place ever again!
Yes, presuming the external demise changed. You can move things around inside all you like and they don't care.
Our buyer's conveyancing solicitor was great (we now recommend her to people, not our own...) and possibly less good conveyancers wouldn't have spotted it, but not a risk I'd want to take given the very small cost of submitting updated plans to the Land Registry.
Also this was a shared freehold flat, if it was freehold house I'm not sure it would matter (but I don't think I'll take the chance now we own one and are planning to extend).