Steps will sort you out.

thanks for the feedback. I’ve booked it in with autoblast. 

Not a recommendation as not in Auckland, but a potential heads up to Mazda BT50 owners...
Mine is a 2009, and WOF guy advised of a bit if rust showing on a seam on underside of drivers footwell/firewall that would not pass next inspection.
Took to get sorted at a local (Whakatane) workshop and during repairs he found the inner footwell was saturated below 2 membranes, meaning the carpet was bone dry and no moisture inside cab.
No holes in floor found and no obvious source of ingress, and no way for the trapped moisture to escape.
I have heavy duty rubber floor mats with 1" sides so not caused by wet boots after launching/retrieving boat, already checked mats for leaks/holes
He suggested I pop the passenger side floor trim off and check under that side carpet as well "just in case".


The only thing I could remotely think of was that I had a replacement windscreen about 3 years ago, and pretty sure the Ute had 2 others before I got it, outside shot, but maybe a small gap in the seal could be a factor? As mentioned, no sign of moisture inside the cab such as window fogging that I get in the car for a few days after driving in wet/damp clothes when caught in rain.