Thanks Jim, I’ll have a look. I’ve always thought of a Barry slip as two points overlaid ( similar to a normal slip but with no straight across path for one route) . It’s the two points being side by side that made me wonder as I need that extra bit of displacement between the frogs
I would have thought that any placement of two turnouts "on top of each other" could be termed a Barry slip. The "normal" Barry slip has the switch blades inside the crossings but Trevor's one has the switch blades just outside the crossings. Maybe we need a distinction of "Inside Barry Slip" and "Outside Barry Slip". Maybe Martin Wynne will be along shortly to confirm.

I think it was he who thought up the term "Barry Slip" to describe the formation.
I might have been the inspiration for the formation. About ten or so years ago I was asked to make the trackwork for the late Charles Vier, another SSMRS member. (Les Bevis-Smith was actually building the layout). I included an "inside" Barry slip in Charles' trackwork to make a change. John Holden, another SSMRS member saw the formation and liked the idea and included one in the layout he was building. It could be that Trevor Nunn was also influenced since I think he was building Trowland about that time. But Trevor was a free thinker and I've no doubt that an "outside" Barry slip was his own idea.
Jim.