I clean a few in South East. An average of £60 sounds about right. I don't do many and are only for the odd existing customer. Some I charge more for but most are usually done inside an hour. I always check their expectations as to what I'm actually cleaning though. I clean the glass, the partition frames, that's it. Not the gutters and not the fiddly finials. If I were to do that I'd consider it a full day's work / conservatory restoration or deep clean. And that s not something Im interested in, leave that to Thomas Sanderson etc. Silly fiddly bits of plastic that crack , fall off, or get lost....no thanks.