Cheers for that Christoph, beats my post processing with timestamps fix!
For what its worth I've gotten away with fairly cheap TCXO's (£15
generic farnell ones) and a GPSDO circuit like the one at
http://ve2zaz.net/GPS_Std/GPS_Std.htm (it did need some manual tuning
at first as the oscillators werent within the frequency locking range
from a cold start) - you do get what you pay for with (double)
ovenized CXO's ones though. You tend to find them on the commericial
boards (theres a mailing list post somewhere linking to a few options)
Tim