TVT 92 Seatpost

[Foreigner]

Looking for some help from TVT92 owners - just bought one in OK-ish condition, will repaint scratches, replace the wheels etc. but that seatpost is bothering me as wont come out. Seat pin is lose, post moves a bit, but the secondary screw under the seat pin seems to be stuck.

Any idea what position seatpost needs to be, to unscrew that little bugger and get it out?

Don't fancy drilling it out