It's all down to experience! You should expect to sting yourself on your first few cleans! Price high and then add another £100, then you might get there. Trial & error....
£280.00 + £245.00 get both then £500.00. That is what i would expect but it depends where you are and other factors . Ed
Kleenaway , i did say other factors !!!! , my quote will be to clean the surface only. I charge the same price per sq mtr regardless what the surface. If you are going down the route stripping, sealing , staining , ect ect then the quote is adjusted accordingly. Ed