Sailing under the Belgian flag, a thing of the past!

[Roberto]

That is very useful to know, including the time allowance for presenting the de-registration certificate.
Thank You for your help.

Chack about the radio license too: I don't know now, but until a few years ago the Dutch Radio Agency did not deliver radio licenses to ships not in the Netherlands, and more importantly the MMSI. Some registration companies have offered licences/mmsi in the name of the boat, but without the owner name (actually they simply declared the boat was theirs), one may not be worried, but it rendered also impossible to have one's own contact names in case of distress (mrcc would have called the Dutch registration company), nor being able to register the equivalent of CG66.
You may want to check if things have evolved since.

 

[MoodySabre]

Belgium together with Holland seemed the favourite countries for Italians to register their boats

Away from the taxman