During a pleasant spell yesterday, I managed to get several applications of Creeping Crack Cure applied to the boot seams where the panels overlap, and along the side where the sealant was originally applied.
I've been mopping up water since I got the car, making good on previous attempts and refitting things correctly, and gradually traced the leak to somewhere above the HK Amp.
This morning, when I went out to check, I was pleased to see no evidence of water despite the overnight rain. I don't want to proclaim it fixed
just yet as I'll give it another couple of treatments to be sure, but, I'm pretty chuffed with the results so far