When you say Bonded line what do you mean?? You cant get bonding from BT can you?? I do know the 2Wire routers thought and they are crap. If i was you ring BT and see if you can blag a Home hub 6 for free? If not then buy your own router and bridge the 2wire to it.
https://www.techwalla.com/articles/how-to-put-a-2wire-into-bridge-mode
There are 2 companies that offer bonded broadband that i know of:-
They aint cheap though, you need 2 or more ADSL or FTTC connections. The phone lines rental, and then they charge for the service per month and sharedband uses data caps.
one of these would be great,
http://www.trustedreviews.com/linksys-ea6900-ac1900-802-11ac-router-review
But they aint cheeap but worth every penny.
Hope this helps,
JK