"That is, with the greatest of respect,
. All MPL courses include an element of solo flying. However, even if they didn't, I wouldn't be concerned. Bumbling around in a Cessna doing VFR navigation has precisely zero relevance to airline flying"
Agreed to a certain extent but the most valuable lessons about my personal limitations occurred by "pushing" it whilst solo. These lessons have given me a healthy respect for the environment we work in (terrain, weather and aircraft).
I don't believe these aviation lessons can be replicated in an airline environment where the captain "carries the can".