Fix data loading problems.

**DO NOT MERGE**
This adds some further adjustments to 'lbc_levels', to make the data load properly.
Targetted against "lbc_levels", as that is needed to make this function.
Note that this fixes bugs in "lbc_levels", not just the known problem with LBPACK.

Probably needs combining with #1439, as due to problem addressed here that is not much use by itself..

**DO NOT MERGE**
Will re-target this PR against master, when #1439 is in.