Dash lights (analogue) not working in my '84 or Just another non-working dash-lights post

New to the Forums here and I'm hoping someone can help me with getting my analogue dash-lights working again.

The story so far:

1. After reinserting my HVAC unit (and radio) the dash lights stopped working.

2. Checked dimmer switch: continuity established.

3. Replaced light stalk switch. Headlamps, turn signals all good.

4. Removed dash display to check connections and light bulbs. All are good.

5. Checked fuses.

6. Determined rear lights are working

7. Side switch-pod lights work.

8. Looked under the dash for disconnected wires. Nothing.

9. Managed to stop the 'It's not the idiot lights it's you that's an idiot.' voice warning.

All suggestions welcome.