3 door seat not moving on runner

[Razorback_Rob]

Like title says. 3 door dturbo drivers seat isn't moving on left hand runner. Right moves fine. I have a suspicion it's stuck on something (maybe bolts raised and stuck on or maybe a coin has found it's way in. Seat is kinda askew at the moment but still In a position I can use.

Any ideas? Ideally I'd take the seat off the runners and see if there's anything obvious but I don't think ill be able to access the holes necessary to take apart. Anyone else any clue?