as for the 650Kg limit on aircraft, there is no safey case there.. just granting someone competitve, or uncompetitive advantage over someone else.
Ultralights,
If you are the aggrieved operator, see my previous post, this is clearly not a legitimate NOTAM. The uses of the NOTAM system is reasonably specific, and this "restriction" is clearly not a legitimate restriction to be published as a NOTAM. There is not much point in just complaining, do something to fix the situation, use the avenues you have, I have nominated two, you probably have other avenues with the local council, despite the local council politics.
Tootle pip!!