Voice does, indeed continue to use the E side pair and is not terminated at the FTTC cabinet (if it was, you wouldn't need the E-side pair link to the FTTC cabinet. You are also right that any noise on the E-side leg will not impact on the VDSL link (as there is a filter) so, in that respect, BB from the cabinet is less prone to line problems (albeit there's the addition tie cable to the FTTC cabinet.

Of course you should determine if the noise is due to your equipment or not first. I have a very noisy phone (on incoming), but it's clearly an equipment fault as a different phone does not exhibit the same problem. If you have access to a second phone (even if you have to borrow it), then I'd recommend trying that along with your main phone as if a fault is found in your equipment then you could incur a large call-out fee. I'd also recommend doing this via the test socket to eliminate household wiring issues (if you have any extensions).

The chances are it has nothing to do with your equipment, but I'd advise eliminating the possibility if you can.

Thanks for the very quick reply.
I shall continue my investigations based on your suggestions.
Appreciated.
Brian

Only an incurable broadband obsessive goes to Cornwall just to photograph comms installations...