Just a quick update... I did the factory reset without keeping recordings and it appears to have resolved the problems which is great. Thanks for your help Shabba. I've marked your original reply as the solution/answer for this post 👍🏻 😀
it was a pain losing all the recordings, but I was lucky and managed to download the vast majority of the lost content on my Sky+ box. It was just a stroke of luck that I had re-joined Sky days earlier after seriously nailing them to the floor with a stupidly good deal - every cloud... ☁️