Thanks for all the advice.
I could read the card in recovery but it failed to format there.
I tried to format in windows but my only options were NTFS or exFAT, no FAT32. But this failed anyway also.
Downloaded a SD format application but this said the card was write protected and to move the lock switch, obviously MicroSD has no switch like standard SD.
So next I deleted all the files on the card and ran h2testw test. This failed and reported card is probably faulty.
Then I checked the contents of the card again and all the original files were back again, so it's definitely 'Donald Ducked'. I was able to get all my files backed up and fortunately I had my photos already thanks to Dropbox & G+.
So I will now look at getting MyMemory to replace it but my fear is they will want me to return the faulty card but it has sensitive information on it that I can't delete. Any ideas on how I can wipe it?