Probably my fault, but this discussion seems to be straying a little. My issue is not with other passnegers and their status, but with the lack of choices.
I accept that Kosher meals can contain fish (but are likely to be pretty substantial thereby reducing that issue). My problem is do BA really perceive "do you want the salmon or the salmon" as a reasonable choice? If salmon pasta is one choice, why isn't chicken salad the alternative? This reminds me of the choice of duck dishes on the Fawlty Towers gourmet night!
Oh, and as an aside, the LGW catering has been getting a lot better recently.