Thanks chaps, sounds like I should try some new SD cards first off.
I use a Hifiberry Digi to get optical out of the pi, works well and means the USB is free, as the USB can get a bit overworked with a wifi dongle ini it leading to track stopping. There are alternatives available now.
I have to power off the pi by unplugging, I only do it when it crashes so there is no software off!
Thanks for those suggestions traildog, I was wondering if that kind of thing existed, an option if I cannot get better memory cards to work.
Oh and it’s a WDMyCloud, has a DLNA server but that’s all.