If you change that to UK and North American operators, you are correct Pax Vobiscum. Here in Europe (you oddballs on the island are not really Europeans
) you can still visit the flight deck, if the cockpit crew feels like it. Done it myself. Granted, I have an airside pass in the UK, but that was not required to visit the flight deck.
There are many differences between the way the UK CAA and other NAAs interpret things.
So, in conclusion, ask. The worst you can get is a no
