... Do we have to accept a dog's breakfast of an aircraft just because there are economic pressures to get it in on time to avoid contractual penalties?
I don't think that's where we are.
I think that the contract tech spec and the various regs that fall from that enforce some aspects of the kit list. Then each of the bidders came to the party with different experience of SAR, in the UK and elsewhere, which influenced their interpretations. As I understand it, in relation to the matters you raise, the two finalists had different approaches that appeared to reflect their recent SAR experience and the aircraft they used.
To be fair to Bristow, they have a history of pushing the spec ahead of MCA requirements. Last year, the GAP aircraft spec took the leap of moving to the Main contract requirements. Rumour has it that the spec may move forward yet again shortly without anyone pushing an arm up their back.