Simple

little sd card. But I needed another as the one I use in the radio to record old comedy programmes is full. So I tried another one 8gb but it wouldn’t work. Eventually I read the instructions to find surprisingly that it will only work with a 2gb card!
Ascertained that my expensive welli boots have a 2 year guarantee so have taken them back to the lovely J from whom I bought and she is arranging for a new pair. Result...