Thanks for your comments chaps.
I know what you mean about the pace of the game with O-Group, but speed of play certainly increases with familiarity and I particularly like the way the rules capture the breakdown of command and control when initially all seems well with a glut of command points and then as the battle reaches its climax too many things need to be done and there are not enough command initiatives to do everything.
One other set of rules that came up in conversation were of course Battlefront from Fire & Fury where the scenario came from, with most of us having a set of them, but many, like me, not having played them, and I particularly remember liking how they replicated artillery fire which I find often lacks in many sets I have played.
Still WWII is so popular there is a glut of rules to choose from, and likely more yet to come and the perfect set of rules are like unicorns, extremely rare.
Cheers
JJ