Having added the four main walls for the cab the remaining piece is the back wall of the coal bunker. This is made from a relatively small piece of brass which needs to be rolled to match the profile of the rear edge of the cab sides. While this should be an easy piece to fit, it isn't. The problem is that given the thickness of the brass and the size of the part it is almost impossible to roll it to the right shape. The trick, apparently, is to anneal the brass which should make it easier to shape.
Annealing is basically just heating the metal to make it easier to work and the instructions say that you can do this by simply placing the part on an electric cooker hob for about 10 minutes. Unfortunately we have a gas cooker and I wasn't sure how I'd support the part in the flames, so instead I decided to use another item from the kitchen, a blow torch. Usually the blow torch is used for melting the sugar on top of a creme brulee or this excellent Lime and Passion Fruit Tart, but I thought it should be able to heat the brass well enough so I set up a sensible looking work area and turned on the blowtorch.
Fortunately I'd decided to measure the part (10.75mm by 23.5mm) while it was flat before I tried annealing it, so I made a replacement using some 0.25mm brass sheet from Albion Alloys. This sheet is slightly thinner than the part from the kit, but not noticeably so, and can just about be formed without annealing. I gently rolled the part using the handle of my modelling knife and then soldered it in place which definitely transforms the look of the rear of the cab.