Are you looking for an mATX case? because pretty much every ATX case supports mATX, you just need to move a couple of stand-offs.
For actual mATX cases you've got the fractal design define mini and ARC mini R2, Also the Silverstone TJ08-E and Precision PS07 (these two are identical on the inside only difference is the front bezel)
The Corsair 350D would also be a good option but it's just outside the price range at £85ish or £95 with a window
There is also the old NZXT Vulcan but the mesh side make dust an issue for that.
And for cheap there's the new coolermaster N200
http://www.kustompcs.co.uk/acatalog/info_0792.html or the ACE ecco 250
http://www.scan.co.uk/products/ace-e...oofing-w-o-psu