Hello Andrew,
Captive or telescopic reducers are a feature on a few rods now, (I have an uptider with one), but the very first one I ever saw was many years ago and guess who made it?.......Harry Barker. (I'm sure it was yours Harry!!).
Anglers and the big casters that used to fish the beaches with the reel low down always had problems taking the reducer in and out between casts and letting sand get in the spigot or dropping and losing the reducer altogether.
Many anglers fixed the reducers in permanently but I remember seeing the one that Harry made and it used a cam to make it a twist and lock type action.
Harry was one of the very first pendulum casters in the North East and a very good engineer.
I prefer to fish with the reel up for a lot of reasons, not least because I'm a shortarse and like to use my rod butt as a wading stick and don't want to dunk my reel. It also suits me and my style of fishing.
Regards Ian
Yeh, I'm a reel up guy also, I suppose that removes the issue of not using the rod at it's full length but I reckon there's a price to pay, your leading hand is not only used to put the power into the cast but also to control the reel at the same time so reel down will get better distance I would have thought. In the right hands like.