but I avoid big companies and supermarket brands of meat, I tend to buy from local butcher who sells non GM meat.
Just a wee bit of misinformation there. ALL meat that you buy no matter whether it comes from a supermarket or a butcher comes from the same place - the saleyards. I don't know where you think that meat comes from otherwise? The supermarkets and meat processors all send buyers out to the sales all over the country. There is no 'GM Meat', unless you consider selective breeding to be GM, in which case you should become a vegetarian because ALL meat comes from selectively bred animals. How do I know this? Because my DH and I breed the animals. The only real issue here is if you want animals that are free from chemicals (from both vaccinations and cross-contamination from the food that they eat), so you should aim for organic meat. It is illegal in this country to use antibiotics etc in animals to boost growth and any claims from companies that advertise as such are using misleading information.