Firstly, I would never accuse Roger (God) Ford of being wrong about anything!
Answering your three questions in turn: -
We have always used the original IEP DfT target price of £1M per vehicle as a benchmark, though this might be a bit of a challenge, given that three years has now passed. The more important issue is the cost and availability of finance from China and the cost of maintenance, which, over the life of the trains will overshadow the capital cost. We believe that the configuration we have chosen will offer the best possible life cycle cost.
We have not yet seen the letter to Sir Andrew Foster that Lord Adonis referred to in his statement. However, the statement makes no reference to Sir Andrew consulting with possible alternative suppliers. Nevertheless, I don't see how he can assess whether the Agility offer stacks up against the alternatives, unless he establishes what the alternatives actually are. We will be deciding how best to approach this issue in the coming weeks, but I assure you I am no shrinking violet and will do my best to be heard.
I am not too concerned about corrosion in the Mk IIIs, having had recent esperience of a refurbishment myself. Actually, if Mk III coaches were considered to be acceptable in the short to medium term, a low cost, low risk way to start with Polaris would be to build power cars to top and tail Mk III coaches. It should be borne in mind however that the refurbishment cost of a Mk III coach is between £150k and £600k depending upon spec. and (though it's not directly relevant) a standard 25 metre Chinese Railways coach sells for £106k NEW! What I'm saying therefore is that by the time you've fitted powered doors (around £75k / vehicle) and retention toilets (upwards of £50k / vehicle) to Mk IIIs, it may be better to spend money on new (MK V?) coaches.
Thanks for the answers! I don't think the letter from Lord Adonis to Sir Andrew Foster has been published yet.