I think the problem is that it's been screwed in too tight - I know new Omnium cranks come with pedal washers as well, whereas on these pedals I can see threads on the inside of the crank. At some point during my battles with it I'm sure I've got confused and turned it the wrong way at some point.
It's possibly too late but I had a stuck pedal in an sram crank.... Took it to pedal pedlar on Balls Pond Road and the mechanic there used a tool designed for gripping pipes on the pedal axle. The more force the tighter the grip. Got the pedal out no probs, axle wasnt even too marked.
I think the problem is that it's been screwed in too tight - I know new Omnium cranks come with pedal washers as well, whereas on these pedals I can see threads on the inside of the crank. At some point during my battles with it I'm sure I've got confused and turned it the wrong way at some point.