Fix issues from testing

[DominicOram]

Fixes #769

Requires changes from DiamondLightSource/dodal#1036

To test:

• Confirm tests pass
• Confirm all problems noted in issue are covered by this PR or other new issues

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 87.01%. Comparing base (b13a68b) to head (e0e8b37).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #796      +/-   ##
==========================================
- Coverage   87.01%   87.01%   -0.01%     
==========================================
  Files         101      101              
  Lines        6970     6967       -3     
==========================================
- Hits         6065     6062       -3     
  Misses        905      905              

Components	Coverage Δ
i24 SSX	72.84% <ø> (ø)
hyperion	96.54% <100.00%> (-0.01%)	⬇️
other	96.58% <ø> (ø)