Something is cooking...

[guohua]

 
...Mr. G. says, Don't be in a Hurry and Don't Be Stupid, Plan ahead and Know Your Targets Body Movements
and pick a Crowded or Congested place, to make your exit from the victim, that makes it harder to remember
what you looked like or what you were wearing.

So in theory, the Skripals may have been infected in the restaurant, the public house before the meal
or anywhere on the walkway known as 'The Maltings'! Even the park where they sat.

Thanks.

Mr. G. Here.
YES!
This would have been my choice of Contact Areas.
A Museum or Public Bathroom is better than a Restaurant.
In a restaurant, I've noticed that someone is always looking or watching people coming and going.
You'd have to have paid for your meal (cash) and then made contact with your victim before leaving, that is Awkward, because if you trip your victim or brush against them ruffly, someone will take notice and stare.
Also, most cash registers have cameras, not an ideal place.

A jogging area or dog park, crowded street while window shopping even a newspaper or magazine stand.