thanks welsh brickie, I've taken your advice on board (pun unintended)
with regard to floor tiles, what thickness ply would you say is necessary to lay on top of wooden floor boards? also how would you secure the shower tray to the floor? with dry mix cement? grab adhesive?
*I've been plumbing for some years now (went to college, got my GNVQ level 3 and all that, for what its worth!) but I've only just started doing actual whole bathroom installs so your advice is GREATLY appreciated. By the way, the house i'm enhancing my tiling skills on is my uncles house so you needn't fear for the customer!