New owner starting through the list of niggles

Some help from the wise would be appreciated. I've only had this beast for a week and the dash has been out several times already. That's why I wanted a Defender anyway - I miss getting my hands dirty with modern vehicles and I want to show my kid how it all works in real life rather than at the end of a laptop.

So... I'm not seeing two out of four red warning lights when I turn on the ignition (before cranking). Batt and oil are present and correct, but brake fluid level and handbrake are not. The oil level light works. I pulled the float from the reservoir to simulate low fluid and, hey presto! The handbrake warning light has 12v so I assumed a dirty switch. I've cleaned the handbrake switch and checked the operation with a meter and it's fine. But the 12v from the warning light are not reaching it.

Wiring diagrams show these two circuits are linked by a diode. I'm assuming that's the best place to look for a break in the circuit but I've no idea what or where I'm looking for it. Can anyone shed light on this one?

The brake level light only comes on when you're out of brake fluid and on mine it hasn't got a hand brake light

Mine doesn't have a handbrake switch either. Easy to tell, just peel back the gaiter and switch will be visible.

Mine does not have an on cap fluid level sensor either, it lights when there is imbalance (leak) between the primary and secondary circuits which is sensed by the valve on the bulkhead.