Hi @ktuite
Thanks for that confirmation and the caveats - really helpful to 'understand' what might be going on under the hood with the blobs.
I'm assuming that the daily cron script is already running (not something I should have set up?) - would it be wise for me to know a manual purging script? Or am I best left in the dark with that comfort that Central is doing its stuff?
You can probably tell how cautious I am with submissions by having posted on the forum before trying it (I know, very un-male of me!) - I have ensured I have local copies of attachments as well as the cloud back ups... Still hesitating 
- I have a redundant form that has some attachments so that's top of my list...
Appreciate the support.