Grant
When I did mine I used the old pieces as a pattern. (I assume you have these) I cut some sheet metal to the exact shape and bend of the inside multi radius curve aswell as the out side curve for templates. I then cut a larger than need block to suit the overall dimnsions. I then cut it very roughly on a bansaw and then used and angle grinder to shape it to my templates. I worked really well. The bracket Jack mentioned goes on the inside of the curve. I hand formed a steel bracket to on top of the wood and overlapped it to the rear frame for better strenght.
Chris, hope this helps
