Thank-you so much for your help. I'll see if there is a rescan database option or something.

Just to double-check I did the double-spend correctly. I just sent the exact same amount to the same address with a larger fee - is that correct?

Just out of interest, the unconfirmed transaction never seemed to appear in blockchain as far as I could see, only in bitaps. This was even before I did the second transaction.

Just to clarify, the 1st trx did not go through. The second one did. If that makes any difference.