When charging for this type of work you need to take into account the costs incurred to complete the work £9 per hour is fine for labour but what about travel to and from and transportation costs plus materials. Don't forget that this type of work needs to done out of hours when you would normally need to pay a premium rate. If you are not going to see a reasonable return then don't bother. Can you make a difference to the floor by just buffing or do you have to strip and reseal the floor if so you need scrubbing pads, buffing pads, Speed stripper, undercoat and high gloss polish and these all cost and it can take several hours to complete. I have a set rate per Sq. Ft and a minimum charge of 2500 Sq. Ft or it just isn't worth doing.