Tidy up error handling

[ryardley]

Sweep codebase for unwrap / Result<T> ensure errors are being passed to eventbus for logging with adequate context. Could possibly make a second channel for errors but it is not required as errors are not propagated onwards.

[ryardley]

If an easy lift ensure we have better error handing especially around external dependencies.

Will put this in a separate ticket but it would be really great if this could decode the EVM error if possible.