Diff, bearings, or brakes?

[Jezza_hr]

Right, I have had this issue since I bought the car and have tried looking into what could be the problem. I have changed the diff oil and have checked to hear scraping sounds on the rear brakes, I also checked for play in the rear wheels, yet I cant figure out what this rubbing/scraping noise is.

The sound isn't a contstant scraping but something that can be heard over 20mph and sounds like it is only rubbing in one point. I am possibly putting it down to brakes due to the high pitch squealing that sometimes happens when pulling away in the morning and the slight vibrations in the brake pedal. Oh yeah and also, when pulling away in first gear it doesnt pull away smoothly when pulling out of a junction, more like it progresses up in a way that it fluctuates pausing slightly as if the rubbing is slowing the car down. Any ideas?