Hi,
Thank you for all your feedback. Much appreciated. I manually ran a Data Age job and the Snapshot copies were deleted successfully. On taking a closer look, I think it may have been down to my job setup. I was only doing incremental Snaps at the time and the next Full hadn't happened yet. I've messed around with settings and timings and can now see the data aging process running automatically as expected. It was all about timing!
Thanks