First of sea cadets around moated building in Kent (5,6)
I believe the answer is:
leeds castle
'moated building in kent' is the definition.
I don't understand how the remainder of the clue works.
Can you help me to learn more?
(Other definitions for leeds castle that I've seen before include "Kent tourist attraction" , "Historic building near Maidstone" , "wrongly suggesting it's in Yorkshire?" , "British medieval palace" , "Keep" .)