As per the title - has anyone managed to pass an allowed caller ID
string from a Trixbox extension out via voip.co.uk?

I am playing with a test Trixbox system hosting two phones and we want
each phone to present a different caller ID to the called party, but the
current voip.co.uk software seems to ignore this. Even withholding
caller ID would be OK but this does not happen even if you set it so
within your SIP accounts at voip.co.uk.

Anyone had more success than me?

Thanks.