Well, I've had some updates that Zen and BT have commenced wrangling, so...

Let battle commence!

BT man just left after 2.5 hours.

He's changed the modem and PSU, which didn't help.

Running the BT Beta speed checker (as you can only run the other one once an hour) we've had results ranging from 6 to 39 meg down.

He's called his support people who of course can't see those results (as for some reason they're not logged - bah) but he's prepared to vouch for having seen them. The fluctuations have been mad.

He's hoping they'll sanction a "lift and shift" to get us onto new kit, but that's in their laps now. They don't like doing that since any kit they shift off of is apparently marked as "ill" and never used again.

He's satisfied there's something screwy going on though. Oh, and yay me, we were the first FTTC off our cab, since we're in port 701 which is the first one in it.

What'll happen next... who knows...

Update for anyone who's still remotely interested...

Final analysis when 2nd BT engineer came this morning:

Manky copper

Lots of problems, error correction etc. on our connection. He's swapped the pair from that line with the other pair to our second line (which has bog-standard ADSL on it) and the problems his kit was recording have gone.

We're just waiting now for the line profile etc. to be reset and hopefully that'll sort us out.

On the plus side, BT now admit it's a fault and it's off our premises, so if it doesn't resolve now, shouldn't be hard to pass it back to them. Yay. And we've now got a new modem, new modem PSU, new VDSL faceplate (as it was the wrong one) and a spare router cos we bought one last week just in case...

And a big HOORAY for Leo at Zen, who took this on board and got things rolling. Thank you!

BT test now showing 29.

Throughput is still 18.

I think they've half-fixed it, or something somewhere needs to be reset. Anyone know any magic words for that?