Matt,
I have stolen a copy of Rays picture from the previous page to try and help........ (but I added some arrows!)
Frame1.jpg
Just out of shot (follow the green arrow!) is a small offset cam held in position with a hex-socket bolt - it is the position of the cam which dictates where the bar should position itself, as it rests against it.
If you have a gap between the cam and the bar, then you need to induce more tension into the system to get it to go all the way - if you have no gap, then the cam needs to be rotated to get the rear deck seal down.
If there is a gap, try pushing the bar down against the cam to see that it is correctly adjusted, and the deck seal sits flat on the bodywork - if it does, happy days!
All that you now need to do is ensure that all pivots are free(ish) to move and then slightly bend the round bar (red arrow) in the vertical plane. This will have the effect of shortening it, and thereby (using the principles of leverage) allow the rear bar to travel further until it rests on the adjustment cam.
It may be easier (well, actually it IS easier) to remove the bar to bend it slightly, but see how much you need to go - due to the leverage, only a small adjustment is usually needed, a mm or 2 shorter, drops the rear seal about a cm.
The problem comes when you try to manually push the deck seal down and there is too much tension in the hood material to allow it to go - this might be either the wires, or the actual material shrinkage. If it is the wires, they are adjustable, if it is the material, then you will need to either wet it and ease it down over a period of time (not ideal solution) or to do it properly, unglue the hood from the frame and re-fit it (time consuming but fairly easy).
99 times out of 100 there will be a simple fix, like lubing up the pivots and bending the rod - basically, AFAIK, the pivots seize up a bit over time and the frame slowly goes out of kilter, causing the tension bar to deform a bit - just need to get it back to where it should be

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