Thanks, all. dc2.0, I had heard of the seatpost man, but figured there’s nothing he can do that I can’t. Your story about the daccordi is my biggest concern as this is a nice frame so I am taking it carefully. I’ve already tried freezing tube, hot air gun and adding penetrating oil for days
My plan is to try Coke first – nothing to lose and then see if I can twist while upside down in vice without going crazy – I worry about twisting the frame as it has machined out lugs so don’t plan to approach it too vigorously. If no luck there (I’m sceptical to be honest) then I will move to caustic and just keep trying until it comes. If it gets to the stage of dissolving the post, that will be fine!
Will post again once there is progress :) .