Hi, Just been searching the web for the TV advert myself and came across your thread. I've looked numerous times over recent years but never managed to find it
. As for your question; the music used in the advert was Vaughan Williams 'Fantasia on Greensleeves' I think they may have also used part of 'The lark Ascending' Both very English and very evocative as you say.
It's strange how something like that can get under your skin and leave a lasting impression; I suppose it's due to the skill of the programme makers and also perhaps the age we are when we experience it. Although only short, it was a perfect combination of film and music. I too am in my fifties and would love to see it again so I'll carry on the search.
Hope this has been of some help.