Forget top quality, there's no such thing anymore

Even the best will come out of shape, damaged, not matching colours, etc you name it.
That also applies to taps, wastes and fittings.
Are you looking at concealed fittings, chrome wastes, the list is endless.
Tiling, will this be done after carcass or will he have to remove the sanitaryware and re-fit afterwards.
As I said earlier a good plumber, for a quality job would be looking for £250 ish a day plus materials, parking etc. in London you could double that, unless you find an east European and take your chances.
Remember on this type of job, is very rare you can go in and finish without waiting for other trades, the tiler being the main man to get the finish spot on.