[alantf]

Hey adrian,
I could be wrong, but it looks to me as if there's something missing from the backrest. Usually, the two bolts on either side that join the backrest to the side supports also connect a luggage rack that can be taken off. If the four bolts are about 5/8" too long, you can be sure that it's because the rack has been taken off & the original bolts used to hold the existing pieces together. It may be worth phoning the lady, & asking nicely if there is a rack. It's not unknown for someone to remove something, put it on a shelf in the garage, & forget about it. A friend of mine bought a hatchback car, & the seller forgot to put the luggage area cover back in the boot (trunk), so don't be shy about enquiring - she can only say "yes" or "no"
By the way, I only noticed this because my backrest/carrier is exactly the same as yours.