Preliminary rearrangement of code re #8724

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Make the changes in LoadFullprofResolution re #8724

Unit test needs adding.

Signed-off-by: Karl Palmen <karl.palmen@stfc.ac.uk>
Merge branch 'feature/8724_support_back_to_back' into develop