Unusual navy trade badge?

[cadmaster]

I have a trade badge, gold on black, 2" wide x 3" high (to top of the arch) with crossed spike & shackle, which I think is for Boom Defence, and with two stars above. I believe that two stars means Leading Rate - I have minimal knowledge of navy insignia - but would normally be one above, one below the basic badge. Is this badge specific to a particular period, branch, etc? Possibly Commonwealth?
I have now attached a picture together with two more from the same source - the larger one appears to be Radar Plotter but a little different to illustrations I have managed to find, the other I cannot identify.

[Andy G]

I think the first badge is a seamanship badge for the Sea Cadet Corps, the central badge is RN Radar Operations and the last badge appears to be another Sea Cadet badge for Offshore Power Hand.

[Nozzer]

Andy G is spot on with his identification of the two SCC badges. I will add that gold bullion cadet badges are worn by Petty Officer Cadets only.

Here is a link to my album which will tell you what you have

http://www.britishbadgeforum.com/for...p?albumid=2347

Andy