I cannot visualise these brackets. But when had a similar sort of problem on an old Clio, I was able to repair it using small cable ties and some epoxy glue. It was a common problem,yet the only solution from Renault was renewing the whole electric window mechanism
About a year afterwards I saw that a Chinese company were now selling repair kits for the clio problem on ebay. If its a common enough fault on the Jazz, maybe someone produces an aftermarket repair kit.
If you cant get the parts, new or used consider the possibility of some creative bodging repairs . The brackets may aid rapid factory assembly, but havnt proved indestructible. There may be an alternative such as a glued repair reinforced by wire etc .