flibble: I've added some decent pictures of the thing so you don't have to wait for Chris:
Secondly, I think druck's getting a little confused between DEC and NCI (Oracle). Acorn were contracted to NCI on a time and materials basis, so it's unlikely they would end up out of pocket.
Acorn were working with DEC on a StrongARM based STB chipset. SA1500 was DEC's StrongARM with an on-chip VLIW co-processor for MPEG decode. The SA1501 was Acorn's companion chip which did the video display - sort of like the IMOD but targetted at TVs.
After Intel bought DEC, they cancelled the SA1500 which meant the SA1501 was useless. That left Acorn considerably out of pocket.
I thought the ARM Development Systems were ARM1. My Springboard manual implies the Springboard shipped with ARM1s (no mention of MUL instruction in the assembler guide, and it has a code sequence for how to do a very slow multiply), and that's dated 17th July 1987. The BBC co-processor is considerably older.