Seems to be OK now
I had previously tried the shutdown restart option. I tried the SD unmount approach and that did no do it. So I bit the bullet and did the reset, and now after a couple of hours I'm just about back with everything reinstalled and configured. You are correct, the reset does a good clean up job and the tab seems to be even more responsive than after the ICS update. And its a good opportunity to clear out the garbage that is little or never used. All the media files on the external SD are found by the media apps from the get-go, and I have not had a message from android.process.media yet.
I use Astro as my file manager, and, after skimming though the forums, thought I would use that to back up my old apps before the reset. I was prevented from reinstalling anything from the backup by Android saying that I can only install apps from Play. Is there any way of getting round this? Anyway, no harm done except more time taken to get everything back.
Thanks for the assistance Mrhelper.