I have a fairly new house which has what i think are called dry lined walls. There is a small gap of about ten mm between the plasterboard wall and the solid wall behind it. I am trying to put some shelves up on the wall but cant find anything that does not pull out of the plasterboard. There are articles on this site about fixing to solid walls and hollow walls but nothing about this kind of wall. HELP PLEASE

Use longer screws and try and push the plug into the masonry.

stu110 is right, you need to get the wallplug right into the masonry. When you drill your hole, make sure you've drilled deep enough into the masonry for the plug to go right in. If you've got a depth gauge set it to the length of the plug + 10mm gap + plasterboard thickness. If you haven't got a depth gauge, you can mark the drill bit with some chalk. Put the plug in as far as you can then tap it fully home using a hammer and an old screw - reversed so the head is against the plug

Nice information.