The chap at Icom just emailed to say that the pcb tracking, a varicap diode and capacitor became damaged by the screws which hold the belt clip on, which he described as "woodscrews"! Now, I am pretty damn certain they are just M3s (and they came with the radio when I bought it, albeit 2nd hand), but there is a moral here, still, which is not to put the screws back in without the belt clip, as presumably the clip stops the screw going too far in?
Anyway, it is good news because while Icom say they have a two week turn-around, mine is being repaired on Monday. Fingers crossed as regards the bill.
It turns out the screws WERE M3s, but were 7mm longer than the originals!