Wow! Some real investigation going on here!
Here are some pics taken just now, the quality isn't great as it's nearly dark, but you can easily see the failing leaves, and - yes - some dirt under the leaves, but I did just chuck the whole plants into the bin, so there maybe just a little Patricia Cornwell (fave writer), coming in here, the dirt may just be splatters...
But the fruit doesn't look right, it smells OK, but here's the killer...
Just this afternoon, when I woke from a siesta, Mrs Growster asked me to remove a strange bug from the conservatory, which is the inside 'wall' of where these toms are situated, in trays of compost and soil.
I thought it was a normal vine weevil which we get a lot of around now, but this little chap looked just like one of the pics in the website you directed me to! It was much bigger than a vine weevil, wouldn't let go of the stick I'd picked it up with, and is still out there now, lurking around!
I'll be on the look out from now on, because, over the pond, we now have a real mystery to solve, and we can all retire on huge salaries with some conglomerate, just because we saw such an event, and you and your son clearly knew what the problem was!
I just love all this!