Cheers for reply mate

. I know I can't get it thru both devices (and tbh, having both does make it look a bit dodgy - but she has a few houses she rents, isn't very tech savvy and maybe just got the cable modem from an old account in another house assuming that it was needed for internet)
I don't want to get it thru both simultaneously though, just the STB. At the moment, I have to switch the coax to the modem if I want internet - not an ideal solution.