Well I could be buggered re self-registration or, indeed, any TM30 registration if, as I suspect, there is no blue house book for the property... If anyone has any good ideas about what to do about TM30 registration in that case please do say...
For a 30 day visa-exemption extension at an immigration office one can just use a guest house TM30 registration, but I don't see this as a viable longer-term plan if I move to a six-month multiple entry visa and thence to a retirement visa while staying in my current rented house 😬