Just wanted to say thanks for the how-to guide, it has been a huge help for me modifying my hazard light switch to allow me to use LED indicator bulbs. The only thing I would say is to be 100% sure which version of the switch you have before you start stripping them down & attempting to modify them as I found out the hard way. I bought a brand new switch from GSF before checking which type my original one was and it turned out the untouched original one in the car was the easier-to-modify 'type 2' switch and the new one from GSF was the 'type 1' nightmare-to-modify switch.
Attempting to modify the brand new 'type 1' switch resulted in much swearing, burned plastic due to really bad access for soldering iron and eventually a totally FUBAR'ed switch! The copper switch contacts setup in that switch is mental and is liable to fail if you even so much as cough too hard on the contacts & getting them out of alignment! Don't mess with them!
My original 'type 2' switch proved much easier to strip further down & gave much, much better access for removing the original shunt & soldering in the new replacement resistor (from RS). I now have fully functioning LED indicator bulbs all round with no hyperlfash issues at all. The flash rate is unchanged and there are no issues with the resistor/switch heating up. My original 'type 2' switch has 'VW Made in Germany' embossed into it, has 4 prongs securing the front of the switch and 3 LEDs on a visible PCB behind this switch front. It also has white paint dots on top of the upper switch casing and on the grey terminal back at the rear of the switch.
Oh and another thing, always make sure you have a spare unmodified hazard switch to hand before you start attempting to mod your other one in case things don't go according to plan. I've gone through two of them now.
So thanks to NooNoo for the excellent guide & for doing all the leg work with regards to the best resistor rating.