How can i fix the boot on my '53 renault megane coupe cabriolet?

The boot switch has long since stopped working on my megane cabriolet, and of course the back up cable effort also does not work, so i cannot open the boot. I have been using the inverted opening method given by dropping the roof . . . but the roof has now ceased to work so access to the boot is impossible !! Short of a gallon of unleaded and a match, does any one have any info on this please ?