"Note: commercial beer/beverage cans, at least here, are copiously lined with "lacquer" so that there is no metal contact with the contents"

Not exactly "lacquer", which most people associate as "varnish" - something you coat woodwork with.   There is a lining in cans, plastic based, and you cannot taste the metal - unless you drink from the can.

"The difference here is that our beer is real living product - it is not a chemical product like american 'beers' it does not react with the pewter like your stuff does. "
What horseshit are the feeding you across the pond? We have "live" beers just like you, and we have bottled and pasteurized beer, just like you. Ale and lagers are types of beer. Whatever type of beer you have will react with metal. Don't kid yourself. CAMRA, while doing great work, has obviously warped the sense of reality across the pond.

"Beer is declining in popularity and a close association with it does the folk scene no good at all. "
So in essence, you are saying that you really need to have half a bag on to enjoy English folk music.