Step 1: Tools & Materials
UK Plug with serviceable fuse
Old AC power cable (or an old HB pencil)
Previous festoon bulb (or tin foil)
Soldering work clamp (or in my case a pair of mole grips)
Step 2: Dismantle Plug
You need to open up your plug and remove the fuse holder clasps. One will have a leg attached the other a wire clamp, we'll get rid of these with the Dremel cutting saw.
Step 3: Build Spacer
I used a section of insulated power cable, but you could use a all piece of pencil. Cut it slightly shorter than the full length of the old bulb. I then wrapped the ends with insulation tape to make sure the core wires couldn't make any electrical contact.
I then removed the contact caps from the old bulb and simply pushed them on to each end of the spacer, you could use a crimper to make them more secure but be careful not to warp them too much.