SWR have tweeted this morning that the main entrance to Twickenham Station is *finally* open after two long years of redevelopment. At long last!
SWR Helpℹ️ Following 2 years of redevelopment Twickenham Station has reopened and the new customer facilities are operational. Please use the London Road Entrance/Exit now.

At last! That's hardly taken any time at all :D
The next upgrades are expected to begin in March.