So were your old light cluster duff (sorry just being nosey). There is a recent thread regarding fitting side lights in the brake light clusters, I thought about sticking some LED's in there. I like the idea of LED's for caravan or trailer light's too, in theory if they are soldered in there is less problems with water corrosion of terminals but this is going a little off topic I guess.
As for your remote key or fob, it really depends what sort your's is. Mine is the older transponder key with the red dot and no buttons, these need a computer plugged in to program these up so may be just a dealer. My remote is the oval type with a red and a black button, we have a workshop on these and are dead easy to reprogram. Replacements for these come up on ebay quite regular but I'm not sure whether there are different types.
If you have the newer key with buttons built in I think these are harder to program. There's a guy on ebay offers to repair or replace the electronics on these but not sure much else about those.
Jim T
PS don't forget to let us know how you get on with the LED bulb's.