
An abatoire woudl be your best bet for Beef tripe, and it can be cut up into pieces b9g enough for his meals. It is smelly and if you cannot face this a pet store with frozen minced meats for dogs shoudl ahve it?
The food you mention I think is popular in Scandinavia among those who work show and breed.
Try googling for their headquarters and asking for a list of local distributors.