I'v been there 3 times (different cars). In my experiences, the seat would try and move but would jam because one of the cables to the gear (there are two for seat forward and reverse) would not engage. As described in the faqs, the cable housing should be shortened, maybe 1/4 inch, on the non-functioning side. In all 3 of my experiences, the seat was all the way back so I couldn't get the bolts out. I was able to move the cable around while moving the control forward/backward and eventually the cable meshed in the gear.
Otherwise, Spook gave you good info. on getting the bolts out.
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Mine: 3-940s running, 3-740 and 1-940 parts cars, and 3 John Deere 630s, dtr1:3-940s, dtr2:2-740s