Just an update on this, got my refund and was told to keep the router, result! As an aside I would also add that I was having major problems with my download speed at the start of the year, repeatedly phone CS about the problem and seemed to be getting nowhere until the start of June.
Never got an answer out of them on what exactly the problem was but I now consistently get a full 20Mb download speed throughout the day
It may well have been that they were upgrading the equipment in my area (South Liverpool), but whatever the reason I'm now extremely happy with the service.