There is an issue. I've had confirmation I can leave the contract as TalkTalk cannot fix the issue or send a different model router.
1) keep pushing that they cannot *@#][!![]'#[@#]!* to you.
2) When they say they only guarantee Wired connection speed - quote website, inparticular "Faster wireless speeds – 9% faster than the closest competition" http://help2.talktalk.co.uk/talktalk-super-router-hg633
3) Quote Ofcom Voluntary Code Of Practice. Read link, as this allows you to now leave even outside the first 3 months. http://stakeholders.ofcom.org.uk/telecoms/codes-of-practice/broadband-speeds-cop-2010/
TalkTalk DO know about this fault, they have done for months, and are now at a point where they cannot keep denying it - and now you can leave with the support of Ofcom.
It took me two weeks of engineers visits, testing wired, wireless, removing faceplate - as long as you go through all their testing and visits, you can then push this detail.