the new update for the dc40 collars say's it will install disabled frequency for non authorised locations and seeing as how the frequency is illegal in the uk best not to update it i fear you may be knackered unless there is a way of enabling it try googling for an answer as there are quite a few dedicated forum's on the astro.
"just found this" The DC 50 is compatible with Astro 320 handhelds that are currently in service, but users must download a free software update to their handheld before pairing the new collar, by visiting www.garmin.com/webupdater. The DC 50 is not compatible with t