Apple Pencil Gen 2 won't let me draw in photoshop on IPad Pro 11 - but I can drag the canvas?

I've tested my Apple Gen 2 pencil in Photoshop. I can do pretty much everything including use the eraser in the app - but I cannot use the paintbrush tool at all. I've spoken to apple and done all the fixes that they suggested and the ability to draw works in Pages, Notes etc. 

But I still can't get it to work in Photoshop... has anyone else come across this issue?

I've heard similar issues with Procreate etc and I'll just return the thing if there isn't a fix as it'll be far simpler just to buy a high level graphics tablet. 

Thanks!