Many thanks for your reply. Yesterday I found it was my fault with the Blackmagic card setup. There are input sliders to set audio in/out. As they were set in the middle of the scale at what I thought was the 50% mark but it was not 50% it was 0%. So you can + or - with the levels.
Silly mistake on my part.
To be fair there are/were a few driver problems after the switch to Win 11 and thought this was another. (Thats my excuse anyway)!