Fix display of homing routine names and some undefined parameter exceptions

[FreddieAkeroyd]

Description of work

• Fix display of homing routine names [homing iitself is fine, it is just display of routine names in GUI]
• Change logic/initialise some defaults to avoid regular exceptions being thrown [To make debugging easier by allowing catching unexpected exceptions as no exceptions are now regularly expected]

To test

Which ticket does this PR fix?

Acceptance criteria

• ** Are these changes applicable to both the old (galil-old branch) and new (master branch) drivers? If so have all appropriate PRs been created **

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Code Review

• Pertitent information has been stored in the wiki
• Have the changes been recorded appropriately in a PR for release notes?

Final steps

• Update the submodule in the main EPICS repo. See Git workflow page for details.
• Reviewer has merged the associated PR for the release notes