>Went to Tesco and bought a hudl for no money instead.
I assume this was a year or so back; Tesco announced in October 2015 that there would not be a successor to the Hudl2 - released in October 2014.
My iPad2 (16GB, iOS 9.3.5) is still going okay, although given the huge performance difference between it and the Air2, it's shortening battery life and limited memory, it has been relegated to 'leisure' usage.
I learnt that the best way to avoid failed apps after iOS update was to ensure all apps were updated before installing the new edition of iOS. Also iOS like other OS's doesn't perform well with constrained memory (less than a couple of GB unused). Perhaps you should do a factory reset and only reinstall selected applications rather than fill the memory.