I found some in a drawer a few years ago but no one would cash them for me not even the banks (UK). In the end they were cashed by American Express themselves.
Get a few quotes for your shipping first, it can be very expensive based on weight and that's before you add on possible tax at this end... I got rid of electrical tools and furniture before coming here as the cost of sending against buying new here for me just didn't make sense.
I moved here 'permanently' and have no address in UK so any correspondence/new cards would have to come here. MBNA closed my account immediately. My remaining card is the clarity card from Halifax. They are OK with my overseas address and mobile number although I've had to confirm details by post rather than online. Their card also has the advantage that they don't apply a foreign transaction charge when used abroad. I don't use it very often but it's a handy option to have.