Radio Switching on/off with ignition
Hello 1900SR, you were spot on, 5 of the 7 wires, where they enter to boot, were damaged and shorting. The rubber tube has always snagged the seal which surrounds the rear screen a bit but it did not show any damage.
I had looked down the list of fuse protected components and found two which related to the Hi Fi/Sound System and checked them both, they were OK. I missed the one covering the Reversing lights/sound system.
Thanks once again for your help all now working as before.