Those tension bolts are made in two sizes (don't ask); if your saddle is the Champion Standard model, it should have been fitted with the longer bolt, and you'll find that a shorter one will be easier to fit in its place. If it's a Champion Narrow, however, it'll probably have been fitted with the shorter bolt initially - in this case (or if the short-for-long substitution still doesn't work) you'll probably have to make a simple jig to enable you to flex the frame sufficiently to re-fit.
Either way, the use of a 10mm. ring spanner on the 'tail' of the bolt, and a screw-driver/chisel at the 'nose', should make the job reasonably easy.
Last edited by tony colegrave; 05-14-13 at 02:34 AM.