ecu is not in the boot
its in the passenger kick panel
under the glove box and to your left, just under the factory flare in that panel
it comes off quite simply and then the ecu sits there.
i dont see why the gauges both died at the same time, because if the dash one is electronic then yeah maybe a wire problem, but if the blitz one is dead thats weird cos its a mechanical gauge.
the vacuum line is all that is involved in making it move.
which means the car is not providing a reading to the vacuum line, which means the line must not be connected.
i dont get any other explanation