I price every job on its own merits, big areas and commercial dictate a lower price small areas with loads of cuts are more, flat M2 rate I rarely work off, but I always work of price never day rate, I make sure I price it according to the work involved, obviously specialist skills, mitres/ bullnosing etc are coated into it, also horrible areas like 16th century cottages that are all scribe work to walls ( I get alot of them). But your average kitchen floor in porcelain with no skirts and no prep I'd be around £35 h £40 pm2 labour only, again this is dependent and size of tile, every job has its variables and those need to be taken into account