In reply to a post by GonePostal:

Just out of general interest, do you know if dialling 17070 on one of the auxiliary lines and getting the "This circuit is defined as . . ." message returns the master number or the "hidden" number of the auxiliary line.

When I worked on these types of lines was before 17070 was introduced (we only had the old 174 test) so I have no idea what it would return, sorry

Just the ‘main’ number.

Thanks.

I suspect the OP is trying to do too much in one transaction , if the BT service ( line and unknown number of auxiliary lines , a PBX essentially) is at a particular location and the Zen line or lines are at another then this is not a number port , porting is a facility to change provider at the current location….so initially the OP should be looking to takeover the BT service in its entirety, with Zen, then ‘move’ the service from location A to location B , as the OP is confident both locations are served from the same exchange, once the service is relocated to the location B ( with Zen as the supplier ) the superfluous Zen service can be ceased, trying to get the existing Zen service at location B renumbered with the BT supplied number at location A ( when they don’t even know how many PBX lines this has ) is destined to fail…the OP criticism is really only of BT , yet as the losing provider they are uninvolved, it’s the gaining provider that is responsible for this either working or not
Once the required number is at the ‘correct’ location , with Zen as the supplier , then a move to VoIP can be arranged ( although this may invoke ETC with Zen ) or migrate the BT service to VoIP ( the VoIP provider solely in charge of this ) then presumably the whole point is that the number is then no longer geographically restricted and can be used wherever the OP likes

Edited by Iniltous (Sat 09-Apr-22 09:37:43)