Lo and behold Ebuyer jack up their price by 33% http://www.ebuyer.com/408613-crucial-4gbddr3-1600mhz-laptop-memory-ct51264bf160bj , I paid £30 . Crucial UK guarantee compatibility of
http://www.crucial.com/uk/store/mpartspecs.aspx?mtbpoid=E4D52BF1A5CA7304 make of it what you will. The memory tested by CMTL should work, it's finding it. I'd probably go the Crucial route.8Gb.