Thanks for your reply and checking this out.
I just took another look at the file in DVD Flick. The name of the file is very long, but it contains this" AC3 5.1 [DXO].
DVD Flick shows two tracks in Properties of Title 1/Audio Tracks - but the name of the tracks is exactly the same, and the Track Language for both is English, although one is Japanese. (And both play on the DVD, WMP and VLC Media Player.) Clicking Edit in Audio Tracks, shows AC3 CBR for both. In fact, Edit info for both tracks is exactly the same.