Hello. Thanks for the helpful replies. Here's the result of about 1.5 hours tweaking.
1 The shadows are much better now. I didn't want there to be just blackness, so I ended up reducing the size of the light source. Seemed to do the trick. Thanks anyway.
2 I just can't nail this one. I re-decaled it but there seems to be a problem with the angle of the camera. I put a test camera in there looking face onto the wall and it wasn't problematic.
3 I think this was overcome by deleting a "duplicate skin" over that wall. This probably occured when points were grouped in 2 seperate groups? Unfortunately it didn't solve previous problem.
Anyway, I'm happier with the look now. Just the wall paper to sort. Also, if anyone has any advice on any other aspect of the pic, I'd welcome it. Thanks.