Thanks for that clarification and for the extra message!
Interesting what you say about the Viscount, because I 'remember' taking a Decca navigator pack out out to a Viscount, on a remote stand, ready for departure to Jersey. However, he didn't wait and went without it.
However, I thought I would try and verify my memory was correct so checked Google images for Viscount flight deck with the Decca fitted; couldn't find a single one, so assumed my memory was wrong. Thanks for re-affirming it wasn't.