It looks as if my way forward is (obviously) to abandon crabbing & side slipping
I wouldn't say abandon it. It's a viable technique for cross wind landings if they can't be avoided. I just don't think it can be a mix. Kind of had to be adapted to conditions.
But for the basics stick with taking off and landing into the wind.
Later we'll work on crabbing and then the knife-edge approach to lose altitude. ;-)