extra protein is a good idea, but that doesn't mean that meat is needed. Dandelion is good at helping to relieve constipation.
it is also very good for detoxification. Milk thistle is interesting, but as a practical matter I find it difficult to make tea from it. Licorice root tea can be a bit expensive in tea bags(15-30 cents a bag), but is only around 5 cents a cup when bought by the pound(a pound makes around 300 cups). In the US it is sold by the pound on Amazon.

I am in the US and don't know about the status of stevia in the UK.

"Bex said that hal huggins says to include some animal source protein in the diet as he has never cured a veggie. so i am a bit dubious about going all veggie."

Going vegan is very hard, but if you eat eggs and dairy it isn't that hard, especially if you supplement with carnitine, creatine, B12, iron and zinc. Trout is not so low in mercury. Salmon or sardines would be better choices.

http://www.gotmercury.org/article.php?list=type&type=75