On the way home I stopped by my local IT shop and picked up a stick of 2GB DDR3 RAM from Kingston. After installing it the netbook refused to boot up.
The local PC World had a stick from PNY. Again the machine didn’t work after installing it, though this time it would boot up but it wouldn’t turn off properly.
In the end I called Orca Logic, a memory specialist from Surrey, and explained my situation. They told me this netbook (and its Compaq cousins) are fussy little things and only accept single bank RAM at very specific speeds. They sent me a 2GB Transcend stick that worked perfectly first time!