DavidReidUK,
Interesting, in the Australian ADS-B mandate there is no place for position information, except from a C146/146 GPS or later, or an FMCS system continually updated by said GPS.
Indeed, there are a number of business jets on the VH- register that are now excluded from upper level airspace in Australia, as their GPS feed is "only" C129.
Tootle pip!!