As there was only one recommendation and I'd already had our pictures hung by the time it was posted, I thought I'd let you know about the company I ended up using (several people viewed the post so maybe you are interested).
I used a company called Art-Install who I was very impressed with. They turned up with every picture hanging fixing you can think of, made recommendations regarding positioning, didn't leave any mess behind them (wore gloves from the moment they walked through the door!) and were quick (important when charging by the hour!).
The main guy is called Martin and contact details are as follows;
07912 222 763
martin@art-install.co.uk
http://www.art-install.co.uk
