High Robbie, yes ,thanks for the reply.
I have a set of billet ally lights that i bought to replace the cheap plastic front indicators.
These lights are fitted with typical lamps for this function.
I was just unsure if replacing led lamps with incandescent lamps would cause a problem, thats why i want change them for led`s.
If these lamps have the BA15s holders you refer to, LED's with the same fitting are available and recommended.
Classic Car LED's will supply anything you need.