Too late!
2 Heater strips made and working perfectly
I measured with the 15v power supply, cut the Nichrome to length, and encased it all inside cloth tape with Felt as a heat barrier on one side to stop heat from escaping into the outside air.
I decided to wrap the heaters around the outside of the dew-shields. It was too much hassle trying to wire them inside.
Tomorrow night I should have it all wired up and fitted
I'll let you know how successful (or not) it is.
Thanks everyone for your help
