Well well well. I've just found the ZyXEL 660HW-61 (bought in about 2004!) and it still works. Flashed it to the latest version so it supports ADSL2+.
I have just plugged it into the test socket and here are line stats it's reporting:
noise margin downstream: 6 db
output power upstream: 12 db
attenuation downstream: 28 db
noise margin upstream: 5 db
output power downstream: 21 db
attenuation upstream: 15 db
According to me (and from checking the line stats on the Draytek), I have just *gained* 5dB on the downstream. That's one hell of a gain if it's correct. The line is currently sync'ed at 11774kbps down and 1110kbps up. Now I just need to move the ADSL modem to its proper home (off the upstairs extension) and see how it performs.
Regards,
Stuart
Zen Pro - "Up to 20Mbit Broadband"