In message , Chris
Allmark writes
I'm still confused .... so basically there are pros & cons to fitting
the enclosure either before or after the tiles?

No I don't think there is, it's much better to tile first. I'm pretty
sure the instructions for my enclosure said that way as well.

The tray is already
fitted, as per the instructions, which show it installed before tiling

Good.

... but not sure about the enclosure. Surely from a sealing point of
view it would be better to be done before tiling?

I don't think so. anyway, an enclosures isn't going too leak there
anyway. My enclosure has a section about say 2 cm wide that fits against
the tiles this is well sealed behind with sealant There is no real
exposed sealant to get damaged or leak.

The weak point IME for showers is where the tiles and the tray abut. The
sealant here is exposed, and damage lead to the potential for leaks
behind the tray, (help though if you have an upstand)

fitting tiles up to the enclosure would require a bead of sealant to
seal, and would also not look so neat a job either

Note I don't have a problem as described by the Ken of a problem sealing
the tray to the uneven tiles. My wall was certainly not upright , or
flat, but my enclosure had a bit that fits against the wall first, to
take up out of trueness and some unevenness, the main enclosure then
fits to this. I've no concerns about it leaking.

--
Chris French, Leeds