Noel. , you’ve done it again! THANKYOU!
Followed your instruction to the letter and all seems to be working again as normal, including rectifying my original problem of real drums being out of sinc with the midi tracks.
Sadly I’ve no idea why what I did worked (I’m not that into the computing side of things) however I’m going to copy you instruction for future use just in case.

Once again thank you. Absolute lifesaver.

Regards and respect to you sir.
Dave