No I bought it from my work intranet so no big deal to ask the guy I got it from for a refund/explanation thankfully!
Thanks for link to video, tried that last night re reclining mechanism, will try again though.
The noise can only be described as sounding like something has been caught in the mechanism, a grinding noise - its's very loud and sudden. Switch off and on again and it goes, only to return in 10-15 mins. We've cleaned the brush and checked the belt and both seem fine.
Thanks again for replying!