Lee. Greetings. This is off-topic, but is very interesting question. I have spent some of my best life years in England during the seventies and the eighties of the last century--my postgraduate degree is also from there. And yes, the term "British", although in this context, I prefer "English", has an almost-always specific meaning in my experience when a product from there is described. It means a very reliable, efficient, and solidly made product that is classic in taste even though may not possess or reflect the latest technology or design attributes. Good examples (from that period) include Roberts Radio and Land Rover Defender.
The English consumer (at least at that time 30 years ago) was generally savvy, well informed and very price sensitive (who isn't?). It was likely, however, that she/he would also be "conservative" in their taste and somehow slow to accept newer models. As a result, I have observed that product runs in England were generally longer than those in the continent. For example, yesteryear camera models were easier to find in England than in France (a country that I am also familiar with). Of course, all of the above are perceptions of an Anglophile at a time that may no longer be representative of today.
Now, what does this term means in relations to Binoculars? To me, it means a pair of binoculars that is closer to Leica Trinoivd BN than to Ultravid or Zeiss HT.
Enjoy in good health.