I bought my Givi EN 370 Monolock top box + "1111FZ" Givi carrier brackets 2nd hand, but unfortunately I do not know where the previous owner bought the brackets.
The 1111FZ brackets are just two arms, and is needed to mount any Givi top box to the NC700 / 750's. You need an additional base between the two brackets and your top box, to mount your top box. There are two different types of top boxes - Mono Key, and Mono Rack boxes. You just need to find out which base will suit your top box, and mount the particular base to the Givi 1111FZ arms. Or should you be in possession of a Givi base for your top box already, it should be quite easy to mount the base to the 1111FZ brackets.
The Givi 1111FZ brackets are easy to mount to the bike, and really looks good.
So I ordered the 1111FZ kit from Givi SA, which is basically Southafricanbike.co.za. Came with the brackets - just under R1100. Would have been slightly more via ebay with a long waiting period. Also ordered M5M monolock Base plate. I just didn't feel like making an adapter plate to use the Base that came with my topbox. Took less than an hour to fit so now I'm really ready to commute with gym bag an all