GWP advice from those into the breed

[Bowland blades]

The bloodline and genetics esp the gene for coat will give you a good idea of conformation, coat and a very rough idea of temperament and drive.
The breeder should give you a good idea of temperament and drive for each pup.
Very few Gwp’s are inherently nasty.
you'll only find out the true potential of the pup properly at about 8 months old. Very few Gwp’s are “tapped”. Most have a high drive, some have a very high drive and a few have a super high drive. All are trainable, some just need a LOT more work than others. The ones that people describe as unstoppable, crazy, untrainable, and end up killing sheep and running into the next county re the ones that the owners haven’t put the time and training into.
go for the best working bloodlines you can find, judge the parents on temperament, then ask the breeder to recommend depending on what you want the pup for.

Nope all are not trainable ! I spent a good while with one of the most successful her trainers who actually stopped taking on gwp from the breed club as he got fed up getting them euthanized.
My own dog was actually pretty well trained but out of tge blue one day he thought it was a good idea to rip my throat out . I won next morning it was like nothing had occurred! Never again for me ( though I have friends who have done well with the breed )