I hear what you say, however, I think there is a reality gap between your expectations of the GA community and reality.
First at my local flying club, there was no warning about this.
Second even assuming that all of the GA community read through or even scan Titles of AIC's (and believe me they do not), the title of the AIC to which you refer relates to the "North Sea Area", which is not likely to catch the eye of the average GA pilot.
Thirdly, the map which acompanies the text is extremely small print and presented in a format unfamiliar to most GA pilots.
Now I appreciate that GA pilots have a duty to keep up to date, however in the interest of safety, the CAA and NATS should promulgate the information in a way which is most likely to be seen and understood by the GA community.
In the commercial environment and in your world of ATC, there are no doubt robust systems in place to ensure that this information is disseminated and complied with. There is no such comparable system for the GA community.
The recent introduction of the new NOTAM system, which throws up masses of irrelevant information is unhelpful and is likely to lead to relevant information being missed by even the most diligent GA pilot because of the "needle in the haystack" phenomenon.
I am simply asking that when such significant changes are made that the needs of the GA community are borne in mind, as it is everyones interest that the message gets through in a clear and concise way.