Can anyone help me to find out the age and value of my dads green square bottle of 12 year old bells whisky

It was a present 40 years ago and is unopened it says
Bells De Lux
Blended Scotch Whisky
26 2/3rds flo/oz
70 proof
Produce of Scotland
Blended + Bottled By Arthur Bells and Sons Ltd
100% Scotch Whiskies

I can post a photo if this will help I just need to work out how!
If you can help me this would make an old cockney gent a happy man and me too thanks Christine