Wow, they went quick... Vic only just found them ! Knibbs also had for around £18. I got one on the bay for the same price but postage inc..

It's a very tricky part to make - I'd really not consider it. but you could just weld a new "prong" onto the old hammer, and grind back to shape - that'd work and the prong dimensions are far less critical than the other bits. It will also need re-tempering, but it's not under much load/stress.