B&W 801 S3 tweeter/midrange head removal

I have a pair of B&W 801 S3 speakers, of which one produces distortion from the midrange-tweeter head.

I would like to remove the head and swap it with the other speaker, to try isolate if the speaker is within the tweeter-midrange, or within the crossover of that speaker (which I believe sits at the bottom under the speaker).

On B&W 801 S2 the head had a screw on top, to loosen it so that it could be removed from the body. On S3, there is no screw on top.

Has anyone had experience removing the head on S3?

Thank you
Thanks for pointing to the service manual. I've found it and managed to disassemble the midrange and tweeter without removing the head.

I swapped midrange and tweeter between the two speakers and found that one particular midrange is distorting the sound. The midrange itself looks perfect. Tested with a multimeter for resistance returns 7.2ohm.

It produces sound, but is muffled and distorted.

Is there any fix I could try or should I just replace the midrange and throw the old one away?