[s9dd]

Right, turns out this was all on Waves installation.

Waves were on the money with the following instructions:
1) ControlPanel > Programs&Features, remove anything by Waves.
2) Delete C:\Program Files(x86)\Waves (or rename for safety)
3) StartMenu > Search "for all files and folders", delete any Waveshell file your system finds.
4) Delete the Waves folders in C:/Users/Current User/AppData/Roaming
5) Run woli.exe, select the stuff you own (which you can check online)
6) Run WavesLicenseManager and push your licenses from the cloud to your device

I would add DISABLE ANTI-VIRUS SOFTWARE before you start, and any executable file must be RUN AS ADMINISTRATOR - right click for that option on the icon.

It's taken a few hours and experiments to solve, but the infamous 7053 DAE errors are gone, and PT 11.3.1 and PT 10.3.10 are working fully.

DD.