I am currently redoing a shower cubical and was wondering whether its best to tile first then fit shower surround or fit surround then tile to it? It will be up against plaster/masonary walls. Thanks in advance

Tile first then fit screen/door etc. If you have an opening for a door ie your shower is a 3 sided wall cubicle make sure that when the tiles are on the door will fit.

Shower tray in
tile Walls
offer shower cubicle in place and drill fixing holes, remove
grout tiles
fix cubicle in place

you can drill the fixings for the shower after but if you have a tile with a deep red terracotta base it is some times easier to do it inbetween as the tile dust from drilling can stain the grout

if its an existing shower you need to take care that the screen will fit after its tiled

i got coaght several times on this with people building the shower cubicle to fit the door and then tiling

which is incorrect

ive had to hack of newly fixed tiles fit screen and cut tiles into frame

so check measrements first

having said that the correct way to do it is as stated above

The only point I can add to already good advice is some shower cubicles have to be fitted onto an impervious surface (ie tiles)for drainage in the frames.

Depending on which shower door you have, you will need to run a bead of silicone down the the back of the wall channels before fixing them to the wall through your new tiles - just check that yo have ample tolerance for the door in the gap if its a door and that your walls are adequately plumb if its a quadrant shower enclosure

Thanks all, it is a quadrant eclosure so I'd better go and make sure the enclosure fits now I've recessed the tray! (plus tile thickness ofcourse!) The plumb walls might be a problem if the rest of the plastering in my house is anything to go by (its relatively new build too!)

This might be too late now but many quadrant enclosures will have some tolerance in the uprights to take into account the variations in your wall.
You will find that you fit these uprights securely against your tiles and, providing your tray is fitted correctly, the quadrant screen should lie properly on the tray.
You should (silicone) seal the OUTSIDE of the quadrant screen against the tray. If you were to seal on the inside this can sometimes force leaks rather than prevent them.
Good luck.