Setting up a sausage factory is "easy". Big room, pork comes in one end, sausages out the other. Lots of expensive stainless steel in the middle and you have to keep the big room cold. Lots of people do it here as everyone rightly says.
Smokeries, at scale, not so much. You have to do all that and then build a smokehouse. Smokers are hugely expensive, the extraction and scrubbing systems are also eye wateringly expensive.
The German factory will receive her pork, spice it, put it in the skins, smoke it and (probably) pack it as well. It will be supplying the spices etc. at their economies of scale, which will be enormous compared to her little farm operation.
Traceability means her farm probably does supply all the Free Range pork if she says so on the packet, if she doesn't supply all the pork then it will be Free Range, if it says it on the packet. (Obviously there are times when people do not follow these rules but I'm working off assumptions that everything is above board).
I note that she doesn't sell any other smoked products on her website, all her bacon is unsmoked so she does not have a smokery and I would venture a guess that everything else is either manufactured with a partner in the UK or on site. (not sure what happens with the chorizo she makes so I'll conveniently ignore that).
I just want to point out it isn't as simple as her not wanting to spend any money locally or just smash out a sausage factory over the weekend. It's an enormous investment, probably a couple of million.