Scrap that last post by me............after a bit of poking about I found there is no need to remove anything, Just a case of using the correct size tork bit and finding the bolt behind the foam insert covering the hinge, push it to one side and tighten the bolt up.............door is fine now. It just goes to show that you can over think things sometimes.
Have just replaced the knackered check strap with one that is at least intact, the bottom door hinge mounting bolt (behind the speaker) is still obviously loose as the door now smoothly rocks up and down as it is opening and closing with the bottom visibly moving. Try as I might I cannot get the foam pushed aside - do you have any suggestions on technique and which side/direction to approach from? I did try grabbing the tip of the bolt to turn it from inside the door (speaker taken off) using 90 degree pliers, but couldn't get enough purchase and the edges of the speaker hole are reminiscent of a potato-peeler with probably the same eventual effect on my fist!