IThanks Vamp, I don’t think that was the problem but it’s very useful info. As an update the performance has steadily improved over the week and today it’s been totally fine.
I had 7GB free data before, which I’d expect should be enough, but anyway did a storage check and deleted 12GB of a video podcasts I’ve never listened to. Performance didn’t improve straight away so like I say, don’t think that was it.
Have you any idea what size of cache the game runs with? And does every piece of data created get added to cache files and it just accumulated until you quit the app, rather than delete once it’s been sent to the DS database (if that’s how it works)?