Thanks for the response Patrick.
I've checked Java and it seems the update I did a week ago didn't stick.
I now have Java 1.6.0_31.
I have started to repeat your test cases:
Scenario 1. Steps 1-4 all good: event created in PB, sync, appear in Google, delete in Google, gone in Google. Step 5: On sync with PB, event remains in PB, still gone in Google.
Scenario 2. Steps 1-4 all good: created in Brain, sync, appears in Google, delete in Brain, gone in Brain. Step 5: sync, event remains in Google, and reappears in Brain, no longer linked to thought.
Scenario 3. Steps 1-4 ok: created in Google, sync, appears in Brain, delete in Google, gone in Google. Step 5: sync, event remains in Brain, still gone in Google.
Scenario 4. Steps 1-4 ok: created in Google, sync, appears in Brain, delete in Brain, gone in Brain. Step 5: sync, event reappears in Brain, remains in Google.
Overall, it probably took me an hour to do this repeat with 8 (?) calendar syncs during that time. And the previous test event that I had reported continues to remain in Brain but not in Google.
You suggested that I could send you more info - what do you need? It appears to be a one-way issue that Google has priority over Brain for updating. Is there a setting somewhere to make it bi-directional updating?
I could take screen shots of the final result showing 2 events (#2 and #4) in Google, and all 4 in Brain, but I think the words say this.
I take it that this is only affecting me? Thanks for your patience if so.