The kickdown switch will not stop the car from starting.
Your fault will more likely be ignition based, from memory these cars had trouble with the ignition ballast (or series resistor) which is situated in the engine bay on one of the flitch panels. If you find it it may look burnt out.
My advice would be to take it to a decent independant who will be able to tell with some simple diagnosis.
Sorry for the vague reply, it's been a while since for me on these cars.