Before though when i was using the linksys on Virgin ADSL it was solid black until the ps3 was turned on then when i turned it off it went solid black again. You could use it to track when i was on it and when i came off it.
Ah, I've just re-read that properly. It looks as though the BQM is pinging the PS3, not your router.
I don't know how it could happen, but it sounds as though the PS3 has somehow got set up to use the Plusnet IP that you used to create the BQM (though I'd have thought that would have caused major problems elsewhere).
get it's address via DHCP from the router, and (probably) be something like 192.168.0.xxx
Could you check it, also that it is using DHCP via the router's LAN address (which will be similar to the one above)?
If it isn't, reset it to do so, delete your current BQM and create a new one, and see if that works. In effect, start again with both the PS3 and the BQM.
If none of that helps then I think I'm comprehensively baffled