I have put some pics in my album, although I'm nearly at 10 posts now. When I said spare GEM2 module, I was meaning an aliexpress clone that I can put the code onto. I had a look but wasn't able to find the original GEM2 until you posted that link, very interesting to see you can actually buy one. The problem with the Aliexpress module is the pins don't line up, so you need to add wires and make the right connections and provide a way of mounting the module. Either way you will always need an original module to extract the firmware to get the serial number.