In my Ph.1, there are recesses:
behind the heater panel
Between the glovebox and the stereo
behind the ashtray
right at the end of the footwell, behind the console and up above where the relays are
under the steering wheel
behind the headlight levelling/dash dimmer panel.
The stereo recess is pretty short, I had an absolute s**t ton of wires to get in too, I found it easier to reach up behind the heater panel and pull the wires down, whilst carefully feeding the stereo in. Then pushing like hell on the stereo to get it in the last half inch to engage the security clips lol. Couldn't get the dash off because I didn't have a torx bit long enough to get under the steering wheel lol.