Understand the frustration, but don't forget the poor lads at Kingswinford are probably being spun the old "it's in the post" stuff every time they chase their suppliers to fill their orders too. I know for a fact that they've really struggled with unreliable suppliers, suppliers taking deposit money and then going bump, and then the process of finding new parts fabricators and suppliers, and getting them up to speed, isn't an overnight job.
Yes, you're absolutely right to be frustrated, but try to understand and be frustrated with the state of the supplier market first. Russ and Gavin are very much the piggies in the middle between us and the suppliers. An email to Julian politely explaining your situation and frustration at the suppliers letting both you and the Westfield factory down is a good way to go, gives them ammo to fire at the suppliers.