An update on this one...
After looking at the various options, I decided to buy a mechanical plunger type switch to do this job as I considered it more reliable and easier to fit than the pressure sensitive switch that came off.
So I bought a switch from AES (Auto Electrical Supplies) over their web site at a cost of about £11. Arrived very quickly too.
The switch is a universal one with one pair of contacts that make when the plunger is released and one pair that break when the plunger is released, so it will work in all situations!
The only slight draw back was that I had to drill out the hole in the peddle box as the plunger is M10 fitting. But the job took about 20 mins from start to finish and I'm very happy with the result.
AES sell a fantastic selection of electrical components and I would recommend them to any member looking for such parts.
-David-