I think I know the ones. They are in the A/C as well, there are two sizes iirc, one slightly bigger than the other.
Its called either a T3, T4, or T5 not sure which though. Southside definately have these, I was looking to get some for the A/C in blue they only had white (normal) bulbs.
Try ebay if you cant get to Southside. You would need to know the type (T3, T4,T5) as its hard to tell from the picture what size is the right one. I think its the T4 for the clock, (not 100% sure though). I'm guessing the number refers to the size in mm, and the one in the clock is 4mm.
http://cgi.ebay.co.uk/2pcs-T3-T4-T5-Neo-Wedge-Xenon-White-Dash-LED-Bulbs_W0QQitemZ200349229098QQcmdZViewItemQQptZUK_CarsParts_Vehicles_CarParts_SM?hash=item2ea5bea02a&_trksid=p3286.c0.m14&_trkparms=65%3A12%7C66%3A2%7C39%3A1%7C72%3A1683%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50How many do you need? I have one working one that I took out of the A/C your welcome to it.