If it's faulty then they should replace free of charge...
I'd say Hub 3. Ask to be put through to broadband cancellations as I'm almost sure they can do the hub 3 free with a recontract. Dual band wifi, ac support and two Gigabit Ethernet ports.
Keep complaining till they send you a free one.
I would have no issues with Sky not giving you replacement hardware out of a warranty period if they were happy to hand over your connection credentials when asked.
Since they won't do that, and instead sort of force you into taking their (in the case of the post-Netgear pre-Q hardware) poor quality options, they should really be replacing them FOC.
For ADSL your speed should be a function of your socket distance from the 'cabinet' - so you can check that via a web-site (broadbandchoices etc) by giving your post-code, if you do that it will confirm whether you would expect 11-12 or 7-9mbs.
(When you said 'your router' is having a problem, I assume you mean the modem/adsl part of the Hub, and also that you are seeing problem when you have a wired connection to hub, so ruling out any wireless problem )