In the spirit of the topic thread, I've had a "chat" (get it ?)  with our new clever friend  
Should there be a comma before the word "and" in the example above
Good question — and this is a subtle one!
Here’s the issue: the comma before and indeed is unnecessary and actually disrupts the flow.
The phrase "and indeed" is a parenthetical insertion, so it should either be set off with commas on both sides or not at all, depending on the intended emphasis.
Better options:
1. With balanced commas (most formal and clear):
...at the writer’s complete lack of grammatical, and indeed, writing, skills.
(But this version still feels a bit clunky because of all the commas.)
2. Cleaner and more natural...
...at the writer’s complete lack of grammatical and, indeed, writing skills.
3. Even smoother (recommended):
..at the writer’s complete lack of grammatical and indeed writing skills.
Having said all that who gives a flying f**k as long as the Swans win at Preston 
