Not really really the best location when it comes to water , as this area is normally the first to flood.
Ive been toying with the idea of moving the ECU for a while know and finally got around to doing it on the weekend.
ECU Normally Lives here.

First I removed the glove box / speaker
Then removed the heater fan unit .
As I have previously removed the AC system , I also removed the AC evaporator housing and pulled out AC evaporator and associated electrics.


Evaporator housing is then re-installed into the truck loosely
With the Fan unit removed the ECU loom and its connections to the Truck loom are all exposed.
The loom can then have the tape etc removed and the ECU wiring split out of the loom all the way up to the top of the dash. Then re-tape the loom again. No cutting / splicing required.
This will allow enough length on the ECU wiring to move it to a new location.
(Seem to have forgotten to take photos at this stage)

Above the Evaporator housing is slot just big enough for the ECU . I needed to cut a bit of plastic off the housing and remove its upper dash mount to clear the ECU.
I removed all the mounting brackets off the ECU , plugged it into its loom , slotted the ECU into its new location and routed its loom behind the heater mounting location.
Then I reinstalled the heater which sandwiches the ECU snugly into its new home.

I would have to know flood the Cab to the height of the Dash to drown the ECU .

Reasonably easy to do but no real benefit to this MOD apart from piece of mind.