Yesterday, I got in touch with Virgin and the very helpful guy there had a look (remotely - clever eh?) at my router and informed me that a lot of customers in my area had been having problems when on Channel 6, despite there being no other apparent signals on that channel.
He changed it to Channel 11 and told me that, although they were currently doing some work on the lines in my locality that might cause some brief outages for half-an-hour or so, there should be no further problems. He also said he'd call me back after a couple of days to see if everything is now OK.
So far, neither my first wife nor I have noticed any more problems.
Perhaps you (the OP) should give Virgin a call.
Will do JBR, sounds like a potential solution.