Pace I understand where you are coming from, but I just sincerely hope we're not looking at more cost to the industry in the long run. Engine changes are expensive!!
The RAF have said ash deposits were found in engines. I take your point that they have not said they were damaged, but I really don't see how you could possibly determine that ash accumulated INSIDE the core of a jet engine without having caused any damage. For me, of course damage was done. No brainer. They are hardly going to sweep it out and that be the end of it.
What scares me the most is fellow professionals convincing themselves that everything is fine. I suppose it makes us all feel better about going flying this afternoon or tomorrow morning or whatever. Like qualifying the RAF's experience by saying they haven't actually said they suffered damage. (No offence meant at all Pace) Common sense seems to have been lost entirely.
As for the visible versus invisible ash question - see ZQA'a link.