I am struggling too, Keith. Not for the first time do I find it annoying, having done the hard bit of solving the clues, only to find that I am not quite on the wavelength of the setter for the final, thematic, part. I agree with your letters and can only think that we need to find "something" within "something" but that is not consistent with the indication that it is three words of 3, 6 and 4.