Don't listen to them, you can beat any BJ game with a strong enough spread. Not all games are going to be as profitable as downtown LV SD games, you have to work with the games you have available.
I'd recommend Hi-Opt II with the Ace sidecount as the best system to beat any BJ game. If you don't want to use a level 2 count and a sidecount, use plain old High-Low and tailor your playing indexes to be risk averse, i.e., don't put at risk an extra 100 pound bet for an expected 10 penny additional profit. The High-Low is almost as good as Hi-Opt II for shoe games but a few times a year I have a SD or DD game to play and I wanted to learn one system that will be very powerful in any situation.
Mind you that when reading American BJ books you guys have that no-hole-card rule over there, so you will never be doubling or splitting against aces and I don't believe you ever do against a 10 either.
The advice you got about Wonging is good, Wong in if you can, and definitely Wong out on bad counts. Also look around for dealers giving good penetration (no not that you pervert) because it can vary from dealer to dealer and a 6D game with 1D or better pen is very playable. Do you have any surrender options in the UK?