According to....1 Jun 2018 14:43
"AIM Rules for Companies" Part I Sect. 10:
"An AIM company must issue notification WITHOUT DELAY of any new developments which are not public knowledge which, if made public, would be likely to lead to a significant movement in the price of its AIM securities."
Clearly, AIM's regulators are hardly as strict as the SEC. But what this rule says is that AIM listed companies do not have the freedom to hold back share price sensitive information - even if this practice is for the purpose of increasing efficiency. I assume that the AIM regulators (as far as there is such a thing) manage this issue a lot more casual than what the rule would imply.
In addition the term "price sensitive" is at least ambiguous. As we PIs would define most of the information we are waiting for as "price sensitive", PM (and any regulatory body) will - most probably - have a different opinion.
Bottom line: I would prefer to be informed of "price sensitive information" WITHOUT DELAY as it comes along and not have to wait for an information package which could take weeks to wrap up.