If any of you are able to reassure me that this is okay/safe, I am keen to try the recipe because it seems so simple.
How impressive ( read taking back the skill from the big chocolate manufacturers) that would be. To be able to make for my friends chocolate!
Depends what you mean by safe
Vegetable shortening is lard substitute. It can come from a number of sources - refined palm oil, coconut oil or hydrogenated vegetable oil - but all are very high in saturated fat, which is why they are solid at room temperature and why they will produce a solid chocolate. They are also cheap and easy to use.
Cheap chocolate is often made using vegetable oil because it is cheap itself: good chocolate uses cocoa butter, which smells of chocolate and is also loaded with saturated fat, but the chemical makeup is nonetheless a bit different. Palm oil, coconut oil contain high levels the fat palmitic acid, which comes with all kinds of health-related baggage; HVO can be high in trans
-fats, which are equally ugly.
Cocoa butter, on the other hand, is very high in steric acid, and this fatty acid is considered to be amongst the most healthy of the saturated fats and may even (in moderation) help lower "bad" cholesterol. It is possible to buy cocoa butter online if nowhere else - it's good for soap making too.
I've started making Nutella substitute at home to avoid feeding the kids to much palm oil: it's not difficult and the results are pretty good - I can't see why that chap's method for making chocolate wouldn't work too.