Well stevepaul, I'm a little younger than you, by a couple of years. The legal age for drinking here is 18, so I didn't drink a whole lot of beer, wine or spirits in the 1970's. I did pick up my game in the eighties but I'm afraid I can't really help you much with the correlation of these ingredients to the quality, or not, of BIR. I don't remember having an Indian restaurant curry before about 1988. An Indian restaurant back then was a pretty rare / non-existent thing where I lived.
There's no doubt in my mind now that the big aroma is Kasuri Methi and in this instance the fresher, the better. I just recently finished the last of my old pack which must have been 2 years old and opened a new fresh one. Boy, what a difference!!! Of course it's also a flavour that I love.
Secret ingredient? Dunno, but I rarely leave beer out.