Various different cultures applaud after landing so no it's not a specific British thing to do.
A big generalisation on my part but your flight being Thomson probably had a lot of inexperienced flyers and most probably have never experienced a go-around. Particularly in turbulent weather and anything deemed out of the norm and it wouldn't be unusual to get a ripple of applause.
Alot of people, particularly people on forums such as this, seem to get slightly irritated at passengers applauding after landing. The assumption is that passengers are applauding the flight crew and whilst in your example yesterday they probably were, this isn't usually the case.
From a British perspective and from experience applause after landing tends to happen on leisure routes. However, it only usually happens 'downroute' and very rarely upon arrival into Manchester/UK which means they are just happy to be on their holidays.......plain and simple.
The odd crew member tends to turn their nose up when it happens but they aren't harming anyone and it can be quite amusing.