Hi Adrian! (Hit the right button this time around!!!)
Sorry to be "a bit of a pain", but your UW side-view set me thinking. At 0:19 of the 0:52 clip, your hand is nicely inclined at some 80 degrees below the surface - but that''s the only backward-facing part of your arm that I can see in any of the down-sweeps/catches. Yes I can understand that some (and apparently you as well) can achieve a proper catch by careful orientation of the hand - but are you "missing out" by not getting a backward-facing forearm earlier "into the picture" (vide page 77 of the SS book - middle illustration, with annotation "The elbow bends and the forearm becomes more vertical in the water.")
If you have tried an EVF style catch, you know the difference it can make, by getting not just the hand, but the forearm as well backward-facing (i.e the forearm at least 45 degrees inclined to the surface for an SS style catch! So maybe, a bit more elbow bend at the catch would improve matters to get more of the underside of the arm involved in propulsion!?
Yeah I know some elites exhibit what seems to be a straight arm pull-through - but heaven help their shoulder joints in a few years time!
However, bravo for your progress so far - lucky chap, you make me feel quite envious!