I have reposted this as I have still not found an answer.

Incoming calls to either my VoipTalk VOIP number or my BT PSTN number are
not displayed correctly on the caller display of any of the DECT phones I
have tried.

I have googled and googled and asked Linksys support but not found an
answer. Only the first 8 digits are displayed correctly. If I look on the
info page of the 3102 the full number is correctly displayed there.

I have applied all the regional settings correctly as far as I can tell but
nothing seems to make a difference. I have the latest firmware.

Any suggestions?