Heres the link for that bracket, i used one with my H75 for a while
https://www.corsair.com/uk/en/Categories/Products/Accessories-|-Parts/PC-Components/Cooling-And-Corsair-Link/AM4-AMD-Retention-Bracket-Kit-for-Hydro-Series™-Coolers/p/CW-8960046
Seems like they're hard to get hold of now, will take some searching, not available on OcUK anymore either.
OCUK sell their own retention bracket for AM4 CPUs, not as high quality as the corsair ones but still does the job in my experience.
https://www.overclockers.co.uk/asetek-premium-retention-kit-amd-am4-hs-04d-as.html
Will work the same for all AIOs using Asetek pumps, which includes all of the corsair AIOs.
Thanx guys will try and get a hold of one for my h100i GTX