We do it the same way as Richy and we loads of flats in Devon.
Pricing flats on an individual "per flat" basis probably won't gain you any work.Pricing for jobs like these is quite competitive.I have a job that is three straightforward blocks of 12 flats with a bit of inside window cleaning. I graft and get the three blocks done in 4 hours. It can all be done from one parking place. I got the job because I estimated how long it would take me (got that dead right for a change) and asked myself what would be my minimum hourly rate for a job that is hassle free and within two miles of home. Also, they pay very promptly, usually within a week. One cheque from one management company.I won't say what I price it at but you will have to trust me when I say that it is a tight one. I don't mind because they don't give me any grief.