Hi - thank you for your response NC Bullseye.
Honestly I’d not tried it knowingly.
I can say with certainty that 6.1.5 was running fine on all betas of iPad OS 13 including beta 13.1. Once the OS got to GM, I moved the device off the beta track as my own app development no longer needed it on that device.
I certainly have a large volume of content in my Infuse library (not coming from my network drive) (~850GB) but that hadn’t been a problem previously.
Let me know whether there is anything else you’d like me to check.
Many thanks for your help