How has Grayling got away with piggybacking Crossrail onto LHR surface EXPANSION when it was designed specifically for Londoners on local routes?
Because it is fully relevant. Crossrail will be a key contributor to Heathrow surface access for all, well beyond Londoners on local routes, and was recognised from the start as such. It will reduce considerably all the Addison Lee etc executive cars which spend the day shuttling between Heathrow and Canary Wharf, because it will be way faster on that than anything by car.
The one thing still not bottomed out, I understand because of negotiating brinksmanship between Transport for London and HAL, is the future of the grossly overpriced (and thus underused) Heathrow Express, when Crossrail comes along potentially at a fraction of the cost and running right across London instead of just to an obscure corner of W2.
[Gatwick] Norwegian claimed they would base 50 787s there !
Reminds me of somebody who based a dozen DC-10s there for a "low cost" operation 35 years ago.