As factual as the posts above are, I think we have drifted away from the OP's questions :lol::lol:.
I don't think your mate is much of a tiler and I would find a reason not to use him if I was you.
The floor needs to be deflection (bounce) free, walls need to be flat and rigid, and properly tanked (I don't know anything about the Wickes fleece) before tiling commences. Porous substrates should be primed with an acrylic primer and use a flexible cement based adhesive.
Search the forum for advice and you will be fine.
Good luck,
Daz