£66 does seem rather a lot to pay for a TG582n. As you are getting a managed install there is also no guarantee which modem you will get. Openreach seem to be supplying ECI's on the last few installs Ive heard of. Unless you can get a Huawei modem, then unless you want to mess with the inards, you wont get any line stats.
If it was me, Id go for something like the Billion or Zyxel (depending on budget too).
The tplink 9970 does seem a good buy for the money, mine should be arriving tomorrow so I'll write more when its been on the line for a while.
There's a full list of available
combined vdsl2 modem routers to see if anything catches your eye.