Six-20 Brownie (UK version) repair question

I just got a Six-20 Brownie, made in London
around 1934-1937, that looks like this:

Dead Link Removed

I am trying to figure out how to separate
the faceplate from the shutter assembly
so I can clean the close-up lenses and
fix the shutter. Any suggestions?

What's in the corners screws or rivets? Any possibility of access from the rear? Some of the early cameras were nailed together.

John, they are screws but the faceplate does
not lift off when they are removed -- the lens
assembly holds it in place. And I tried to
unscrew the lens assembly, but it does not
want to budge.

This one is not fastened with nails, but there
are three screws inside the camera, around
the back of the lens. I am thinking perhaps
they hold the camera frame to the faceplate.
But I was hoping to hear from someone who's
familiar with this camera before plunging ahead.