Slx M7000 oil pressure caliper/ lever seal probems

Hello all,

I have a 2019 bike eith slx lever and caliper. Noticed the rear brake wasn't holding oil pressure...saw oil around banjo nut. Tightened and thought this would resolve the issue.

I put fresh oil in attempted to bleed brake...30 mins...but of frustration and still no pressure in level. There's no oil leaking on caliper hose or lever. I'm totally baffled. What steps cam I take to test the 3 main ( lever, caliper and hose components individually...to find the faulty component..?

I haven't found anything on YouTube!

Thanks,

Jon.