I think you should look at this thread about DMC first (and don't get too shocked):viewtopic.php?f=16&t=13673
I would say that your wife is probably quite a typical case of Thai women who might have previously been going to their local temple but never received much instruction or education about the Buddhist teachings as such, so when they end up living in the West they tend to visit the nearest Wat Thai to seek some social connections with their compatriots and home culture. I wonder if it is the Dhammakaya temple in Woking where she went? If she went instead to a more "normal" Wat Thai, like the one in Wimbledon, she would probably continue pretty much as before; with Dhammakaya, however, she will receive lots of input from the missionary monks and DMC channel which can really get her hooked. This is a deliberate strategy and it is a great money making religious business, not much different from other such groups in Christianity. They use the same "marketing" approach which they learnt from other groups.
Some Thai women, especially from Isan, have had some strong connections with the forest monasteries in their home villages and that is the reason why they will come to a place like Amaravati or Chithurst even if they have to drive longer: they say they have faith in the Kruba Ajahns or the masters of this lineage. Dhammakaya, on the other hand, is a relatively new minority sect within Thai Buddhism which still remains a fringe group, but it has managed to gain a following of business people and politicians who actively promote it (such as the current Thai prime minister). They are better trained and organized than most other Thai Buddhist groups, and they keep a high standard of discipline which is inspired by their teachings on karmic retribution vividly portrayed in their video animations of hell realms. Normal Thai Buddhists will tend to be rather lax around drinking and so on, and accept it as normal that one breaks a few of the precepts regularly (which is not so good of course and has been criticized, but the Dhammakaya type of morality smacks of evangelical Christians with "fire and brimstone").
This excessive devotion to the Dhammakaya leader, to which Thai women are more prone than the men, can cause real problems with their family life and relationship to husbands who do not share such devotion. Thais are primarily "faith types" (saddha carita) whereas we are more critical and sceptical as Westerners. Some husbands manage to ignore their wife's strange behaviour and beliefs as long as it does not impact their life too much. But it would be hard for a Western man to convince his Thai wife that her ideas about Buddhism which she got from DMC are seriously distorted in some important respects: she will tend to just believe what the monk says. The best idea would probably be to physically move away from the temple, but even then the TV channel (DMC) will be available anywhere you go...
But one trick you could try is to make her watch or read the teachings of some other popular Thai monks, such as Ajahn W. Vajiramedhi: http://www.dhammatoday.com/index.php
He comes to England every year now and his teachings are simply standard Buddhism which he knows well, adapted to deal with modern themes that are relevant for modern people. Some people criticize him for his big media exposure, and predict that he will be corrupted by such publicity as other monks before, but the good side of this (and he does it deliberately) is that it acts as a counterweight to the DMC channel and reaches a lot of Thais through the internet, Facebook, Twitter, and so on. In this way, although it might seem a bit superficial "Dhamma Light", at least they get a wholesome and positive guidance with some Buddhist principles which they can apply in their lives. His titles such as Anger Management have been translated into English too:http://www.dhammatoday.com/index.php?op ... 54&lang=th