Ipad PDF expert documents missing

Hi everyone,

I have PDF expert version 7(with the latest update) running on iOS13.3 on an iPad Air 2. After updating from iOS 12 to 13.3 approx 3 weeks ago - my 50-80 documents in PDF expert are no longer visible. I can download new documents into pdf expert from my NAS/dropbox but dozens of documents that were there and extensively annotated are not.

When I check storage usage of PDF expert it shows 6.7GB of documents/data in use - but no files are visible in pdf expert.

Can anyone think of a solution? I'm considering "offloading" pdf expert and then re-downloading it from the app store to see if the existing data of 6.7GB can be found and used again....

Any other ideas ? any help appreciated.

Thankyou

Pete

ps: I will add screenshots later today