As an american, I have to say that you all take this stuff far too seriously. The police around here shoot people if they're getting out their driver's license in a 'suspicious' way. ( Sad, but true. About 5 times so far in the last year. Just in this city. Wild, huh?) We tend to tiptoe around them and be very VERY polite. Yes, sir. No, sir. Keeping my hands where you can see them, sir.
The concept of the police using their firearms responsibly and as a last resort? Wow. That would be great. If your dog snarls at a cop here, he's already got his gun in hand and is preparing to empty the clip into your cute canine friend's cuddly face. As far as tasers go...yeesh. They use em on 11 year old kids, dogs, homeless people, paramedics who get in way, motorists, bicycle evangelicals, your granny, their own granny, students, people who look like students, etc. Sometimes they use em on an actual criminal, but it's just a happy accident really.
So chin up! Your cops may be ill-trained pet snuffers, but they sound charmingly old world and not likely at all to mug you for meth money.
On the chip subject (crisps, whatever) I had to look up Marmite. Used brewer's yeast? So...beer flavored chips?! I... am aghast. England is obviously holding back their advances in potato snack science, which we in America desperately need. Be warned, english! We hunger!