My bath came with metal brackets to fix to the wall rather than relying on a batten which would obstruct the brackets. I also fitted service valves to all my fittings, including the bath. Long flexible tails on both hot and cold make it easier for idiots like me to connect the supplies, IMHO. Getting the waste to line up was the trickiest part; I had to think about how many degrees of freedom there were in the various possible combinations of parts I had available.

What trouble did you have with them? They seemed fairly straightforward to me.

Ah, haven't noticed any problems yet.

Regarding the metal clips, tho ones I have seen only hold the bath into the wall not up. With wood floors the joists shrink up to 6mm and so the bath feet move down a bit stressing and usually opening up a crack where it joins the tiles.

With a batten this can't happen, even retrofit baths want a batten every time, it also makes it really easy to fit them.