I can't see the Regulator will allow hiking the current landing fees etc to pay for the extension, this is against all the concept of regulated charges. They already disallowed funding of the Crossrail rail extension HAL previously said they would do, which as far as Heathrow is concerned will not require any capital investment on airport property, and will presumably likewise take the same view of capital investment for the future being paid for out of current operating charges. The whole cost quoted for R3 looks substantially gold-plated anyway (I think they are putting in land costs at current valuation where quite a lot of the required land has already been steadily acquired by BAA/HAL over the years), which I hope the regulator has the professional advisors to identify.