Db exception detail

[psa]

Make it easier to debug write attempt failures by logging the error from SQLite.

Check List

• [x] I have read CONTRIBUTING.md and added my name as a Code Contributor.
• [x] Contains logically grouped changes (else tidy your branch by rebase).
• [x] Does not contain off-topic changes (use other PRs for other changes).
• [x] Applied any dependency changes to both setup.cfg (and conda-environment.yml if present).
• [x] Tests are included (or explain why tests are not needed).
  • Simple text change in error logging
• [x] Changelog entry included if this is a change that can affect users
  • Trivial usability improvement
• [x] Docs not needed
• [x] If this is a bug fix, PR should be raised against the relevant ?.?.x branch.

[oliver-sanders]

(closing and re-opening to sort the tests out)

[psa]

LGTM, tested as working.

@psa, did you get to the bottom of the write error?

We're still working on it, it only shows up every month or so, so it's been a bit of a pain to debug.