How to remove the grill panels from KEF...

C35 speakers?

I would like to tighten up the grill cloth on a pair, but cannot figure out how to remove the front panels. There is no inside access from the rear of the cabs, so I am guessing that there might be some sort of a release mechanism around the front edges, or are they friction/tension mounted?

Tried a bit of force with no success, but did not want to go too hard in the event that there are such catches (as not to damage them).

They are late 80's sealed bookshelf's with the tweeter mounted in the center of the woofer.
Grab the side of the grill frames at the vertical center. Pull outward (away from the center of the speaker). Next pull slightly forward (away from the front of the speaker).
Hi Lee:

Thanks, I finally got them off "intact" with a towel wrapped butter knife. Very odd four point center positioned mounting system, but it works well.

I have since sold them to a local phile who will be picking them up in a week, or so. I am only hanging onto speakers that have efficiency specs in the upper 90's (have SET/SE 2A3 and EL84 amps plus a push/pull el84 that I hope to triode - not much power in the bunch).