I do not know whether it is good thing to look at old adverts but this is from a 1954 motorsport but even then I would have thought a complete K3 engine and gearbox for £15 was a good buy.
Off the top of my head: The K3 was not Ex Gardner, but 003 which prior to the 2 seat body had the Ex 007 offset body on it. Not the first time it had been advertised as Ex Gardner. The Yovil J4 is probably J4004, which did not sell & was broken up by Colvin soon after. Dad had the radiator, diff (still in J2396) wheels & a few other bits, but did not recognize the Ex Hamilton lightweight body! The Rad eventually went to Mel Jones & is still on his old J2. As he said to me "our world was an Aladin's cave & we didn't know it" JH