Pace Of Training

[yak sao]

but the few times we do spar I find myself reverting back to my karate / kickboxing background because even after a couple of years I don't have confidence in myself with it.

That's why I find it important to train slowly and without a lot of undue pressure with new students. It takes some time to ingrain new motor skills and reflexes into the body.
If you pressure test too soon, you will simply revert back to what you are comfortable with.