jerryf: "Castle should have consulted and hired RISC OS Ltd to do RISC OS 5 in the first place"
Castle never needed to "consult and hire" RISCOS Ltd to produce a 32-bit version of RISC OS, that was part of RISCOS Ltd's original mission statement. Castle only went it alone when nothing had appeared several years later.
Without wishing to be rude, it seems that you're commenting on some quite involved "political" matters behind RISC OS, without actually paying any attention to the reality. Please don't try to mislead people like this!