it seems Albert Hall was correct,the extension has no start date until sometime in 2023,
're quote from airport manager below:
Mr Szalay told the event he was concerned about finding the staff required to keep up with demand.
“When I speak to people in the construction industry, finding the right skills and building the runway extension next year is going to be a challenge. But once that’s built, the staff that take us up from 700 to 2,000, where are they coming from?” he added.