About £60-ish. Try another switch first.
Just trying to figure my loom / switch fault as i split the loom down again and lost the pictures! They are not the standard colours which don't help
For new heat elements (waeko for example), it looks like you have to leave out/bypass the heat sensors/resistors.
I read somewhere that if the sensors in the pads are faulty then they will stop the elements from working correctly. If that is the case then the aftermarket pads might not be a straight forward swap.
Adding the mk3 switch to a waeko kit may just work on full heat if you can live with that. Still not tested it yet myself but will update.
I'm using a mk2 switch, a mk3 loom and mk3 pads.
The diagram