I got this one from Amazon
http://www.amazon.co.uk/gp/product/B..._dh05vb76PSBR0
Very reasonably priced at £8.99, comes in a range of colours, strong magnetic clasp, sleep function works well and fits perfectly. OK, not real leather, but has a nice smooth finish (better than some "real" leather ones I have tried which have been tough as old boots) and is robust with no signs of wear and tear after 3 months of constant use.