Richy, Richy, Richy ...
I believe that if your employee was doing £200 a day (day in and day out) on domestics and was costing you - including wages, bonuses, n.i.. fuel, insurances, bits and bobs etc a day plus use of a van etc so an all up £150; well then I reckon you should kiss the ground he walks on and thank him for the £250 pw he is lining your pockets with.
If you are paying a £100 a day (including van fuel etc) and he is only getting £64 (8 x 8 ) and you are expecting £300 a day - day in and day out then you are seriously deluded. It means you are hoping for £1000 pw gross profit per week from a turnover of £1500 gross per week from one man.
Cloud cuckoo land.