Thanks for the link, I have downloaded the batch replace script which defiantly wasn't in the v12 or 8.8.3 install zip's so no idea where that went

Any way I have ran the replace_dlls script (with Admin cmd prompt) but still no change (no video, no sound) looking at the script and doing a search for the msvidctl.dll & cpfilters.dll on my PC shows about 6 versions of the files dotted around (c:\windows\system32, c:\windows\winsxs, c:\windows\syswow64 and the memorable folder: C:\Windows\WinSxS\amd64_microsoft-windows-video-tvvideocontrol_31bf3856ad364e35_10.0.18362.1_none_c10dba5b005177b0) which none had changed versions
I ran the script again which I don't think threw up any errors but as the window only appears for a few seconds I had to record it on my phone to watch in slow mo. I noticed I didn't have the tool nsudo, so downloaded it of majorgeeks added to the install bin folder (remembered to unblock it) and still no luck, I even rebooted!!!
so ran the uninstall ran the installer with the thumbnails & replace dlls and bish bash all working again.
Many thanks