Try carefully slitting down the length of it a couple of times with a Dremel cutting disc or similar. If you don't have one, try cutting through the seat with a junior hacksaw making the cut in a helix around the seat and then peeling it back. I would start with one slot with the Dremel first and try to open the seat out by twisting a screwdriver in the slot.
If you don't have a Dremel, first cut off the moving screw collar, then the fixed hood with a hacksaw. Make a careful diagonal cut (about 1") on the top or bottom of the reel seat. Carefully lever this up with a screwdriver then, using a pair of long-nose pliers, wind the rest of the seat off corned-beef tin key style. Done it loads of times with cheap Fuji-type copies and it works a treat.