Well, I think we should club in & buy Nigel E some heating for his study - though the fact that it was too damn cold in there for him to type a response did result in a phone call from Nigel which was great.
Anyway - Nigel advised that it may pay to lubricate the sealing rubber around the bottom of the hardtop where it rests on the tonneau cover lip. Also, strapping the soft-top may also help.
Well, I put some silicone lubricant on the sealing rubber & into the catches that locate over the frankenstein bolts. I also put some cloth over the rear tips of the soft top rubbers, as it looked as if they had been rubbing on the inside of the hardtop. Didn't worry about the straps for the soft top as it seemed to be sitting nice & quietly.
Et voila - golden silence (well almost - the induction roar from the CAI was as gratifying as ever

). But nix, nothing, nada, silencio from the hardtop.
It's usually the simple things that work best ....
Regards,