Thought it was time I updated this...
After hearing peoples advice on here I booked the car into Reno so they could get a technician to take a look at it. I then stupidly cancelled the appointment as I thought the noise was quite minor and not making it all the time.
Roll on to last month and I could hear the noise much more loudly. Booked it into to them and they looked at it, agreed it shouldn't be making that noise and was probably a problem with the timing. Due to this they wanted to get my car in ASAP. Reno offered to cover it under warranty, so I left it with them on the Monday evening. Car was then ready on the Friday where i found on picking it up the old belt, pulley and arch liner. Went back in and explained this to the service guy (to be fair who has been OK) and they sorted it. Weird thing was there was no paperwork with the warranty work, is this normal?
Roll on today and I've noticed it is still making exactly the same noise, if not worse!
From what I can gather (from seeing the bits they left in the boot) the bits they changed are the aux belt and the bottom pulley, so not the actual bits that actually need replacing.
Its going back there on Wednesday where hopefully they'll agree to actually replace the correct bits.