I think it's a case of getting in a good supply that most of us freeze their food. I freeze freshly shot rabbits to kill off the internal parasites, also any fleas that might be on them. I don't go in to town that much so have a weekly delivery from a butcher in the next village, so as I have enough to feed 9 dogs in a week I have no choice but to freeze it!
Food bought from the local butcher or supermarket is fit for human consumption so it should not be contaminated with anything so it doesn't need freezing to kill off things where dogs are concerned.
They do need bones in their diet but not as much as you think, between 10-20% bone is fine, the emphasis should be more on the meat but they do need bone.
The stuff being sold at Pets at Home, is it just chunks of pure meat?
Sounds like it might be worth you contacting someone like Landywoods who do home deliveries of frozen raw food for dogs, there's quite a few members on here that order from Landywoods so I'm sure they'll chip in and tell you the things they buy and what they think of things in general
Sandy