plumber & electrician first fix, tiler, plumber and possibly electrician* second fix.
I expect you’ll need first and second fix plumbing, for loo and rad/towel rail, shower. Most stuff butts up against tiles so it’s just as easy to get the plumber in either side of the tiler.
* Electrician might not need to come back depending on what exactly you’re installing and where it’s located i.e. lights/underfloor heating can all be sorted before tiling and shouldn’t need any further work but extractor fans/cabinets with power sockets may sit over the tiling and might need to be wired up after the tiling is completed. Also depends how competent and willing you are to finish of the last few electrical connections.