Many thanks for the replies .
I'm currently in the middle of a fresh install of Windows 10 on my PC, so can't try the suggestions at the moment. I was hoping to use MC 25 on this fresh install.
To hopefully clarify a bit more, this what I remember happening with MC 24 before reverting back to MC 22 a couple of weeks ago.
I start the TV Set Up Wizard and complete all the various pages. My Hauppauge tuner is recognised all the way through. As with MC 22, I opted for OTA set up for the TV guide. As soon as I select "Scan" for channels, Media Center errors with "No TV Tuner Found or is Currently in Use"
When using MC 22, this error doesn't happen, the channel scan completes and the guide loads.
If you need further info, please let me know. MC 25 will be the first thing I install when Windows is finished.
Thanks again