Sometimes it's the simplest of things...

Have had a bit of a wiggle at the wheel between 30-40 MPH since changing out the wheels some time back.
Not the alignment, not the wheel balancing, not strut aging, not suspension play.
The answer was hub-centric wheel adaptors.
ECS has them for ten bucks + postage. Worked like a charm!

Sometimes it's the simplest of things...