For me that is a £30 account, and I'd consider it very fair at that.
Having said that, after a couple of cleans you are goingto be knocking it out in no more than 30 minutes tops, so at £25 it is still good money.
But I wouldn't be seen dead doing it for that price off a ladder
The problem with these larger properties is that they are a walk in the park for WFP, but you have to keep the prices on a par with what you would charge if you were doing it trad.
Otherwise it is a slippery slope downwards in prices
WFP even if DIY is still a relatively substantial investment, and running costs are higher, drop your prices too low and you will end out earning no more than a trad cleaner...yet you'll have higher costs.
No time to write more, gotta get back out there!
Ian