Hi Peter,
Just found your post.
Yes, Tommy at Affordable has them in stock.
No more breakages for me so far – touch wood. I did try welding the first one that broke and I managed to get 30 hours use out of it before it broke again. However, by that time I had managed to get another so it wasn't an emergency any more.
Both of the broken steering knuckle showed signs of cracking for extended periods of time – part of the casting was rusty. Whether that was from excessive use on my part or poor casting work, I'll never know. That being said, I am more careful these days.
When you put the new steering knuckle one make sure your tow in on the front wheels is to spec. I would also check and strengthen the tie rod by putting a steel bar inside the tube to stop it bending.
Hope all works out ok for you.
Cheers
mariner