Good Afternoon,
Sounds like you have succeeded in detaching the barrel from the front, but I took some pictures and might as well include them for anyone reading the thread in the future.
Front facia is attached to rear switch barrel by 4 lugs at quarter hour points, one such point
The red arrowed tabs are location stops and the yellow arrow the lug.
In situ the lugs protrude through small windows, one such here.
The top of each window is a delicate strip of plastic, that as audifan says must be eased over the lug with a thin wedge of some kind. The strip is very likely to break ,
!
This switch was being swapped out for a hard touch switch and was scrap as far as I was concerned so no loss, I suppose if it mattered and great care taken damage free removal is possible. Very easy and suitable for a superglue repair if required!
Should have said pull the thumb piece to fog position at the start. To confirm the front thumb piece will pass through the hole, pic halfway through.
It takes a lot of force and some marking might occur, but it will go through! Maybe a touch a silicone grease might help and quickly wipe it off once through, in fact the housing must elastically deform a touch to allow this.
I agree this is no way how the switch was originally assembled but I cannot see a way of separating the thumb piece and spindle from the barrel. My guess is the barrel was assembled with the spindle but not the thumb piece. The thumb piece was then bonded to the spindle from the front once the barrel was in place.
Hope you have removed it by now.
Andy