I’ve got a bit of a niggle on the inside of my left knee. I guess I need a cleat adjustment.

Heel towards the crank? Any perceived wisdom on this?

New bike/pedals/shoes? What has changed to bring this on? What makes you think a cleat adjustment is what you need? Not saying you’re wrong, but there could be dozens of reasons for that niggle.

New cleats on the shoes.. and a new bike

Have you still got the old shoes to compare or was it just new cleats? Are the cleats in the same position exactly – most cleats dig in to the shoes slightly so it’s easy to tell if they’re in the same place.
New bike I’d also be checking all the other bits like saddle height, fore aft, angle etc. If the cleats are the same it’s other things that have changed to cause the problem and likely need to change again to sort.

Can you switch to flats for a couple of weeks to
a) ride gently without pain
b) observe where your feet naturally want to align themselves when not constrained by cleats.

That might give you a bit of insight into why you are getting this pain suddenly

Check this out Knee Pain

Amazing the difference a tiny adjustment makes.

2mm lateral positioning is the difference between walking. Or not for me!

I use speedplays purely for the amount of adjustment you can have.