This article is from the Model Rockets FAQ, by Wolfram von Kiparski with numerous contributions by others.
There is only one event that I have come across, which is the "International
Rocket Weekend", which is held near Largs, Scotland. This is run by
STAAR Research (See addresses below) and is held on the August Bank Holiday
every year (Note that Scotland does not have a Public Holiday, only England
There are no formal rules and regulations like the NAR, Tripoli etc.
The basic rules and events are laid out beforehand, but often change to suit
the interests of those attending. The event is aimed at promoting model
rocketry in the UK, and often has a number of beginners. There are also
many 'open/experimental' sessions for the more experienced.
The most important thing is that everyone enjoys themselves.