Update:
I have a new set of original 'Rothmans' decals on the way, together with a slightly used set of wheels, fresh Rally block tires and a NIB Tamiya front stabilizer set. Another money pit, waaheyyy!!
The restoration can begin now. I have successfully tested the brakefluid-paint-stripping-method on my Saper Sabre project. DOT4 brakefluid doesn't react with the lexan, but dissolves even multiple layers of lexan paint. DOT3 shoud work even better, but haven't tested yet.