Well, I finally took a punt on this stuff:
And it really works! I wasn't too hopeful when it arrived since it appears to be made in Poland and the instructions were in broken English, but it does exactly what it claims. I suspect it's been created from all the good old chemicals the EU has illegalised, because it smells just like the wonderfully effective old Araldite used to before they buggered around with the formulation to conform with the new environmental regs. So I've ditched my plans to burn the house down and collect the insurance and the missus has stayed the divorce proceedings. :-)