I'll explain a bit better here, hopefully. ...
An office we've been doing a twice weekly clean in for a couple of years have recently had some remedial structural work done on their top floor. They've asked us to clear up after the builders . . basically a load of dust all over the desks & fittings, inside of windows was 'orrible, carpets a bit manky, etc. . .
The office area affected isn't massive and it took 6 man hours to get back to normal. We've agreed to itemise on our regular monthly bill, but I'm not sure on whether to charge our standard rate + a certain %, whether there is a more scientific/accepted method or whether it's a straight-forward "this much" type scenario?
Any advice appreciated . .. just don't want to undersell the company/service.
Cheers.