It does look a little "effeminate" but Antler have a bag that measures 39x28x17. It comes as part of a set, but argos (don't worry, they deliver so you can avoid chav hell ) sell it for £15 - http://www.argos.co.uk/static/Produc...er/0754909.htm

I know it's technically too deep, but bear in mind if you have a bag that's 16 cm deep and you stuff it to the gunwales it'll go above the limits.

Antler also have a laptop case that's 44x33x16, expandable to 20 - http://www.luggagetogo.co.uk/modules...s&manuf=Antler.