lets put it this way dpf, you can do a tilers job but not all of them can do what you can do!
i'd set up another business as mr republic said..do high end bathrooms, wet rooms and maybe a page of stone patios with some bespoke mosaic feature?? just an idea (although i'm usless at this marketing lark)
you can do all the tiling, sub prep, bespoke feature work and sub the plumbing out..in might take a year or so to really get off the ground but if you aim for 1 full bathroom a month then thats 10 days work covered each month to start with.
and when you turn up at these posh gaffs and show then your pool and spa work, well i reckon you'd practically have the job already mate
ed