Just done my footwell lights. Bought white 501's from local car accessory shop at £4.50 for 2.
Passenger side bit fiddly to get enclosure out of footwell, then need a small flat head screwdriver to prise lens away from enclosure. Original bulb slides out easily, new bulb bit more awkward to re-fit as its a bit bigger, but does fit OK.
Driver's side more awkward. Need "star" screwdriver to release panel under dash, then light pulls out from panel the same as passenger side.
My LED's didnt work 1st time in; was advised to turn them around. Work perfectly now. Nice white/blue light shining.

After seeing Kenny's pics, might change again to red to match other cabin instrument lighting. Thanks for your tips Kenny.