A little bit of lateral thinking.

ADSL and VDSL normally work on both legs - there is a serious drop off if on leg is dis. That suggests that there is some form of isolation between both legs and earth at some point in the path from End User premises to Exchange. For VDSL that must happen at the cabinet whereas for ADSL it is back at the exchange. So, just wondering if rather than it causing a problem with the VDSL signal, it is suggesting a problem with the analog line would be caused.

Just a thought ... and for me it is 25 years since I was designing switches with various line interfaces.

Did BT not give a reason why?

If you have a standard NTE filtered for ADSL there's no physical reason I can see either why you can't have FTTC.

My guess is it's the BT Openreach records for the line preventing the product from being ordered. In fact, if it's what I'm thinking, itwould prevent any broadband product being ordered i.e. ADSL2+

Ask BT to get the installation details for the line and tell you what the Termination Type is. If it doesn't say Line Box then that's the problem.

If they are unable to tell you drop me a PM on here and I'll try and help.

"Hello Earth" this is....... Line

Seriously, I have an analogue PABX and FTTC. Engineer install as they all were in 2011.

However, the PABX is a purchased one simply plugged into the NTE with faceplate VDSL filter.
Could it be that the OP's PABX is a BT supplied one? Otherwise how would they know it exists? ISTR that 2-line PABXs at one time had to be supplied and wired in (no NTE and plug) by BT.

Cheers!

Thanks all!

I will chat with BT today and have the conversation first hand

Let us know what they say. However, you are unlikely to get someone with a good technical understanding of the issues, they will probably say "because the system says you have XXXX".

Just curious if this was ever resolved?