Hello Mark,
There was an extensive thread about the scuttle vent seal a number of months ago. This should be helpful.
WRT removing the flap, one must remove the three screws that retain the mesh screen to the flap. This will allow you to lower the mesh screen into the air intake plenum and will expose the nuts that retain the flap lid to the hinges. Pay attention to any spacers that may be located between the flap lid and the hinge. I had to shim my lid to achieve proper flushness with the cowl when I reassembled the system. One more note, you’ll need to place the mesh screen into the well of the plenum before you bolt the lid to the hinges. It cannot be fitted afterward. Once bolted to the hinges, you may pull the screen up into position and may then screw it to the flap lid.
I hope this helps!
Brian