May have had an upgrade to adsl2+ from adsl

My experience indicates the opposite. Since my exchange installed FTTC my ADSL speed has dropped from 1.9 Mbps to 1.6 Mbps. The normally low speed is due to my being 2 miles from the cabinet (rural area). I suspect this present drop may be due to the interference with the cables in the cabinet when they connected the fibre cabinet as we have experienced a change in speed on previous occasions when work has been done in the cabinet.

In reply to a post by yarwell:

haven't seen anything to be honest. If the power masks are correct you shouldn't see much if any interference from the VDSL. I've never seen much crosstalk effect between ADSL lines, and I have two to play with.

I have although it usually turns out to be down to a run of cable somewhere that's not using twisted pair, The effect can be quite dramatic as well.

In my case it was down to [censored] internal wiring, went from 20Mbit/s on a single line to 12Mbit/s and about 6Mbit/s removed that cable run and got about 18Mbit/s on one line and 22Mbit/s on the other.

Seen another instillation where adding a 2nd line didn't boost throughput as expected due to extensive crosstalk, in that case it was a rented apartment so I couldn't rip out the cable to replace it.