I came across this pic at Bois de Boulogne, Paris. It may be from the DGJ article Dean mentions below
Dean's comment from 2011
"In the Autumn 1993 issue beginning on page 82 is Don Whittaker's story of his European pigeon-shooting adventures of the early 1960's "Preparing for Europe". Early in his tour, after losing a few too many birds, he retired his Purdey for a Parker DHE that would shoot 86% patterns from both barrels. He mentions a couple of shells he used but never discussed how they were loaded even though he also mentions Bob Brister in the article. There are two not so good pictures of his Parker and it has a single trigger, a pistol grip and a BTFE but doesn't appear to have a ventilated rib. He has the safety taped forward and it looks like he may have taped a spacer pad to the side of the already wide "trap style" comb."