Thanks for your suggestions Tom, Vince.
I was also worried about the maintainability of the modification to StdReportEngine, so will look into how to create a new report engine as suggested. And the suggestion to rename from AWSCLI to AWS-S3 make a huge amount of sense az Vince points out AWSCLI does a lot.
No promises on timelines though, this desk thing called work keeps getting in the way.
And in answer to your query on World-Read to the bucket, that is what the Bucket Policy PublicReadGetObject does and why we didn't set the permissions when the bucket was created