21CN exchange with ADSL2+ router, only ADSL1 sync?

[#1]

Hi,
Are there any circumstances where a 21CN connection, and ADSL2+ router, will be forcibly connected at ADSL1 instead?
Noticing my Darlington exchange is now 21CN, I've had my account upgraded to Plusnet Premium. I also bought a new ADSL2+ router (Zyxel P660HWP, latest firmware).
However, my router always falls back to ADSL1 (router says ADSL_G.dmt). If I force the router to use ADSL2+ only, i.e. disable the auto fallback, then it never syncs at all.
While my ADSL1 connection is perfectly reliable, I'm very puzzled as to why it never uses ADSL2+
Is this unusual? Thanks in advance..!
Andrew
p.s. Maybe the following stats are useful. It's obvious the high frequencies have too much attenuation, does this mean ADSL2+ is totally unavailable?
noise margin upstream: 19 db
output power downstream: 16 db
attenuation upstream: 29 db
tone  0- 31: 00 00 00 02 45 65 77 88 88 88 87 77 76 55 55 34
tone  32- 63: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  64- 95: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  96-127: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 128-159: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 160-191: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 192-223: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 224-255: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 256-287: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 288-319: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 320-351: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 352-383: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 384-415: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 416-447: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 448-479: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 480-511: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
noise margin downstream: 15 db
output power upstream: 12 db
attenuation downstream: 50 db
tone  0- 31: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone  32- 63: 09 9a aa aa a9 99 99 99 99 99 99 99 99 89 99 99
tone  64- 95: 07 88 88 88 88 77 88 88 88 77 77 77 77 76 77 77
tone  96-127: 77 66 56 76 66 77 76 66 66 66 66 66 66 64 66 54
tone 128-159: 55 55 50 55 55 44 04 44 04 00 03 33 02 00 00 20
tone 160-191: 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 192-223: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 224-255: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 256-287: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 288-319: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 320-351: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 352-383: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 384-415: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 416-447: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 448-479: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
tone 480-511: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00

[#2]

Plusnet will have to move you to ADSL2+. You can raise a ticket or wait for a staff to pick this up tomorrow.

[#3]

Thanks Caveman - I already tried raising a ticket, though several days later, still no improvement.
Interestingly, the first ticket response was an apology, saying Plusnet have now migrated me to ADSL2+. It looked like a standard reply though. Further ticket responses just assured me I'm on an ADSL2+ account.
But, like I say, still no ADSL2+ sync.
Any more ideas?

[#4]

Can a moderator close this thread?
I've jumped on the "How to tell if you're really on an ADSL2+ enabled line ?" thread instead, as it seems to describe my problem, and there is a good resolution rate.
Thanks 

[#5]

dick:green Thread locked in favour of this one at the request of the OP.