I have fitted a Givi adaptor and box which were designed for the OE rack and they fitted perfectly. I needed to buy a stainless spacer for the rear bolts, I think the rack is meant to go with the Adventure pannier frames. I'll post some pics if your interested.
From my understanding the box I have just acquired should hook/clip straight on to the GSA rear rack (which is what I think i need)...no need for photo's but thanks for the offer.