Thanks Paul, I'm hoping a lot of the issues are due to connectivity problems at my end (free O2 wifi on-site) - I'll keep testing.
When the Collector app actually crashes on Android and prompts you to report the error, does this error report actually find its way to Esri or does it just go to Google?
Pete - yes, we can access crash information logged in the Google Developer Console so please send it along. It may or may not be enough information to isolate and find the defect. It is always a good idea to log what you find with support as well. For what you did send to Google - what device were you using (it provides that information with the log as well)?