Our landlord was great and we told him we were buying a house once offer was accepted but that we would give official notice once we knew it was all ok.
The process took far longer that expected due to us being messed about, then xmas when all associated businesses shut for a week or so.
We gave notice once we had paid deposit and signed paperwork. I prefered having a bit of overlap, which worked out well as the stupid seller we had was very disorganised and was still moving her crap out at 9pm!!!
We moved in a few days later and I had time to clean rental house properly. No way would I arrange to be out and move in on same day.
Ah, really? I'm 99% sure it doesn't fit onto those two categories - looks like a family home (which is why I love it!).
A chain would actually help a little bit as without going into details we will be a little slow getting a mortgage offer as we have to sort out our tax credits claim, so at least there'd be less chance of them noticing we were holding them up a bit!