Staples are good.......
http://www.staples.co.uk/search?x=0&y=0&keywords=filing+cabinets+2+drawers&ajx=1
We've got something like this - http://www.staples.co.uk/filing-cabinets/cbs/223349795.html?promoCode=&Effort_Code=WW&Find_Number=223349795&m=0&isSubscription=False
Easily big enough for...