Andy Hall wrote:
For a wall mount pan, I am wondering whether to go for ply or plasterboard
(ply seems to make more sense as less risk of crushing) and again whether to
tile behind or up to the pan.

Ply and tile behind the pan. As another poster mentioned, most wall
mount bogs have an optional pad to eliminate squeaks.

I am going for a wall mounted tap for the basin

http://www.hansgrohe.com/com/en/prod...om.mixer/washb
asin.html

http://tinyurl.com/q86mn

I bought some Axor stuff for our shower room - by far the best prices I
found were at http://www.megabad.com/ - fine site, not much English
communications were a bit cranky but they came through fine with
stereotypical efficiency, excellent packaging etc. The wall-mounted V&B
loo alone was about half the cost in the UK, including the shipping.

This does not have the plate escutcheon and so I will need to cut tiles
carefully to fit.

I have an electric disk type tile saw for cutting straight pieces.

The question is how to cut the curved shapes or drilled holes for the tap.

Hole saw - presuming you are using porcelain you need a diamond one.
The Armeg screwfix ones work fine, or there are cheaper chinese
non-guided versions around.

Or align the holes along tile joints and nibble away with a wetsaw.
Looks less neat though, and forces the rest of your tiling to comply
with those spacings.