I changed all my instrument lights to LEDs recently, including the parking light bulb (RID bulb still to be done, but that's mildly complicated, need some dark evenings for that one!). I'm very happy with the result.
I got the parking light LED bulb from fizzmo.co.uk (an ebay shop). Good service. Recommend them. Tor the push in T5's in the instrument panel, i got these on Amazon (x10 for £6.99 - bargain). The outfit selling them is called xtraled.com. Again, service was quick. Their ref number is: HM-6145-YNGS
I think there is a big choice of sources for these bulbs. So you could just search the web and i'm sure you will find something.
Oh, just make a note that LEDs only work when the DC current passes through them in the right direction. If you fit a bulb and it doesn't seem to work then take it out and try rotating it 180 degrees. Failing this reverse the spade connectors on the light fitting (parking lamp in particular).
Good luck