If the SAR services are to be privatised I presume they will rely on ex RAF/RN/army personnel to crew and maintain the helicopters.
Given that PFI has proved to be a failure and that a private consortium will make money out of saving lives wouldn't it be a more sensible to purchase the helicopters (I'm sure a finance packages are used for military procurement similarly to the private sector ensuring that at least we own the helicopters) and use full time reservists to crew and maintain the helicopters etc.
Using ex RAF/RN/army personnel would enable the UK to keep trained personnel "in house" without the requirement to house them etc.