Vectra 1.8 SRI noise from R/N/S is it the bearing ?

I have a Vauxhall Vectra 1.8 SRI 2002, it has a loud rumble type noise which gets worse the faster I go, over 50MPH it is very loud, just come back from the tyre depot, and both rear tyres were worn, the N/S/R was the worse but the wear was uneven and it looked like it was worn even more so in patches around the tread, since fitting new tyres it has become quieter (just) but not sure of the problem,it was mentioned to me that it could be the rear wheel bearing hub, any ideas or how to test/check it myself, or would it be best just to put it straight into a garage ?
Thanks in advance for any help.