The problems aren't new, there are days more noticeable then others. I know my way around technology as my house is filled with it, also I was using the hub in router mode but due to slow downs, I am trying to see where the problem is.
My wife notices in both her laptop or iPhone, buffering on youtube or facebook videos. I notice more on my Mac as is what I use the most.
Iff it is the standard superhub 2 then i would sugest turning down the transmitter down on 2.5Ghz to the middle and same with the 5Ghz, and have the channel set to auto and aso keep the router away from cordless home phones as they transmit at 2.4Ghz, keep in a well open aira aswel, try disconecting a few devices as it could be struggerling to disterbute even amounts to lots of devices try hard wiring devices with ethernet iff possible will put less strain on wifi, iff everthing els fales ask virgin to check your power levels to see iff they are within acceptable levels.
I have just had an idea what might work do menny of your devices use the 5.0Ghz iff that is not used disable it as iff i remember correctly i hade same problem with the normal superhub 2 and disabled the 5Ghz and that stopped the cut outs