MB wrote:
I'm constantly having problems hanging heavy items in our new build
house, which is constructed with dry lined walls.

It's a bit of an old chestnut, this - if you google the archives of this
newsgroup you should find a fair amount of info (and possible solutions)

eg:
http://groups.google.co.uk/group/uk.d-i-y/browse_frm/thread/348e30b8f20bc39f/ac544f2c5e6c5dd8?hl=en#ac544f2c5e6c5dd8

David