I had same exactly same issue. The Rose side of things has been excellent. I sent the brakes back to Rose UK, good email communication. However the brakes were then sent on to Shimano UK and you can probably guess this went tits up from there.
Shimano UK didn’t replace, they refunded Rose, without telling them or me! After some chasing up it was decided that all SLX and XT brakes in UK and Europe were out of stock. I’m just waiting for the replacements to finally arrive about 3 months later! I believe though that this may have something to do with a hose/banjo/caliper redesign as the problems were so well documented, but I haven’t heard that in writing.
If replacement brakes are in stock you should be OK but use the Rose UK email contact Fin Paton.