[Closed] LED bulbs in old Dynohub set ups?

Got an old bike with sturmey archer dynohub lights. Reading web forums, it seems possible to out cheap LEDs put in place of the dim halogen bulbs - has anyone actually done this?
Are there LEDs with built in regulators so that resistors/electronics fiddling is not required? (Bike does not have the dry battery unit, and I am not bothered about having a stand light (yet).

I know that Reflectalite offer 2 LEDS plus a regulator for about £30 - too expensive, looking to spend as little as poss!
Cheers