Agree with Basil. The financial arrangements have been pretty thoroughly analysed. From the point of view of the investors ( pension funds and the like), probably the most important thing will be a guarantee from the regulator that the RAB formula which generates the revenue flow will be fixed for the payback period, and clarity on how various contingencies such as everything from cost overruns to terrorism risk will be handled. Probably there will be floor and ceiling type arrangements but this sort of financial engineering is known territory.