I found somewhere to photo-copy the design onto the press and peel. All for the princely sum of 20p.
Haven't got any pictures of transferring the design onto the metal. Basically I used an iron and a combination of techniques I got off the internet. I think I may have had the iron too cool ('Nylon' setting) when a thread on Chop Cult http://www.chopcult.com/forum/showthread.php?t=7840 recommends the highest setting.
For my first attempt I'm using brass with PCB etchant from Maplins. Set up is shown below, simply put parcel tape around the outside of the design and on the back of the metal add a parcel tape handle and bung it in the acid.
While I was waiting for the etchant to do its thing I prepared the next piece to go into the acid.
Reasonably happy with the result but not happy enough not to try again tomorrow. This time I'll try warming the acid to speed things up.