I find the Antec 300 over rated on our forum. The case isn't the worst case in the world, but at the same time is nowhere near the best < £50 option.
Id borrow another £10 for,,
Coolermaster CM-690 Dominator Case - Black [CM-690]
£59.98 inc VAT
http://www.overclockers.co.uk/showproduct.php?prodid=CA-145-CM&groupid=701&catid=7&subcat=29
I love these cases for < £30 let alone £50
http://www.overclockers.co.uk/showproduct.php?prodid=CA-160-CM&groupid=701&catid=7&subcat=29
I've built a few using them but need a front 120mm fan.. Even so, they still come out < £40.