I don't remember what they call it across the pond, but here in the states people can contact the city offices for public services to see if any of the local civic centers are offering a course like that.
You can also check with large cake shops, hobby shops, and probably even in the newspaper for those types of services and classes being offered.
Here in the states, some junior colleges even have those classes during the summer months.
When in doubt, ask some local cake shop owners.