I didn't play it but I did recognise it when I checked the solution.  Similarly structured words like atilt, atingle and astir are all rare.  Is aquiver better known than words like these?

Yay!  Thanks Alan. 

While it's true that words like orate, orated and orating don't come up very often in everyday conversation or print, frequency of usage isn't the primary criterion for commonness.  It's whether or not a reasonably well-read native English speaker would know the word.  I reckon if you know oration and orator, you'd also know the root word (even if you don't use it all that often). 

1.  Some time ago I requested that orated be reclassified as a common word.  Alan had a different view and decided to make it rare, along with orate.  Since then, a few players have questioned that decision and I've found it problematic, especially considering that oration is common.  I'm not sure of the status of orator and oratory.  If they're both common, that would support the case for reclassifying orate and orated.  If they're not common, they probably should be.  So, Alan, I'm asking you to please reconsider the status of orate and orated.

2.  Also some time ago I suggested adding the words vape, vaped and vaping to the Chi lexicon.  Alan agreed and added them as rare words.  Since then, I think the words have become much more widely known.  I doubt there would be many people today who don't know what vaping is.  So, I'm requesting that vape, vaped and vaping be reclassified as common words.  (I'm not sure whether vaper was included in Alan's original judgement.  I'm not too fussed about its status.)

Me too.

Glad to hear you're on the mend, T-Rex.  Hope to see you back in the game soon. 

It's sad state of affairs when the most stable figure in Downing Street is Larry the cat, who has outlasted four Tory Prime Ministers.