I think the grammar entry should be changed to 〜はさておき in general.
I agree with 誠
In the old days, それはさておき was often written 閑話休題.
The は in それはさておき is pronounced 'wa' instead of 'ha.' I had some doubt whether it was, so I asked somebody in the office about it.
I went ahead and changed it to 〜はさておき
閑話休題 is 当て字？ but it does give the feeling of a 閑話!
bamboo4さん, the pronunciation in the dictionary is different: 閑話休題 【かんわきゅうだい】 (exp,n) Now let's return to the main subject, To return from the digression,.. (in a conversation, speech, or story-telling)