Would I have failed?

Recently passed here, but I keep replaying one part of the test in my head wondering if I'd have failed...

We're going down a normal 30mph road, the middle of the road becomes a turn lane and so I enter it and wait to turn right. Traffic is coming towards me, a car flashes and signals me to go but I stay where I am and only drive on when there are no oncoming cars. The reason for this is that my instructor said not to lose your priority, and that a pupil of his failed due to letting a bus pull out of them.

So, would I have failed if I'd have turned right when they flashed for me to?