IAG have reportedly submitted a counter-proposal as part of their submission to the Government consultation on the draft Airports National Policy Statement.
Citing the quoted costs of bridging the M25 for R3, IAG have proposed shortening the proposed 3500m runway by 300m, so that it would stop short of the M25, apparently overlooking the fact that the published plans show nearly 1000m of R3 (not including the RESA) extending to the west of the motorway.
It's a shame that IAG couldn't afford the cost of an up-to-date OS map that has the line of the M25 shown on it.
International Airlines Group issues Heathrow M25 warning