Ok, finally got it!
I was so focused on running in VR that I did not think to make adjustments with VR turned off!
So, as a VR only user, the procedure that worked for me to create/populate a saved games, DCS, config, view, SnapViews.lua file was as follows:
Launch DCS World in flat screen mode, VR not running.
Select an aircraft and spawn in on the ground. In my case the TF-51D.
Go to the cockpit view settings for the selected aircraft. Note the move camera keys and the save cockpit angles key.
Go back into cockpit view for the selected aircraft and use the move camera keys to alter the pilot/seat position. Then save new position using the save cockpit angles key.
Close DCS World and open and check the users, name, saved games, DCS, config, view, SnapViews.lua file.
The file should now appear and be populated with DCS aircraft type details all listed in type alphabetical order.
As a VR only user of DCS I had not realise that the SnapViews.lua file could only be created/populated by actions in non-VR mode.
Although I had used the SnapViews.lua file on my previously installed version of DCS World with VR, I had also previously used it in flat screen mode with TrackIR prior to moving over to VR; so I had taken it for granted that the file would be there no matter what.
Thanks to everyone who helped me work through this.
Happy landings,
Talisman
Solved at last!
Solution: In DCS Options Audio settings I turned down In-cockpit from 90% to 60 initially and finally settled on 75%. Can now hear ATC better and can understand sling load voice assistant at last.
My earphones (win volume mixer) now set to level 58 and DCS Audio settings as per screen shot below.
Thanks and happy landings all.
Talisman_VR's post in New Installation - VR head position was marked as the answer