Okay so I was driving back from my mates yesterday and this noise just appeard out of nowhere, it sounded like two things rubbing together maybe? when i got faster it got faster and slower the same, then i had a quick sharp brake and it went away (disc brakes in rear if that matters) then again today the same happend the faster and slower then sharp on my brakes and its gone, just wondering if any1 has a slight idea of what it might be?

Brake pad rubbing on disc due to sticking caliper?

Hard to know without more info on the type of noise...

so I was driving yesterday and this noise just appeard out of nowhere,

I get this a lot, it's the wife sat in the back

Yeah its kind of hard to describe thye noise without using sound

A friend had a stone lodged in the caliper once and that took him a while to find.

Best way is jack up one side at a time and spin the wheel to find which side has the problem.

I get this a lot, it's the wife sat in the back

So ,you've let her out of the boot, then

Seriously- rear brakes - drum or disc ?. Either way , moley's suggestion seems the best way to isolate it. If drums, could it be the retaining screw workd loose ( as some service place hasn't tightened it enough . ),and it's got between the wheel & drum .

Most likely a stone, as others have said or possibly pad lost it's material & is now metal-to-metal.

Only way to find out is to have a look!