Thanks Mikeandjane, what I was trying to get at regarding the £85k threshold, is whether income from a guest staying past the first 28 days of their stay is included in this - there is some HMRC guidance that suggests 29th day onwards isn't electable for VAT, but it is ambiguous as to whether this is for holiday lets as well, or just for hotels.
Regards your tax year point - the £85k limit is on any 12 month rolling period, not just the personal tax year! A very important distinction some could get caught by if not aware!.