I last saw this 550/4 of mine in mt late teens so about 30 years ago, I spent 6 months building it in my bedroom.I lived in Haywards Heath at the time.
So the Registration is FLP674T it was registered 30/5/79,it was none standard unlike my later F2 but is was dark metallic blue with a white frame, stainless home made rear mudguard and polished crank cases.
It could be in a shed or garage, I just hope it wasn't scrapped.
Thanks in advance.