Your brake light switch is too old. The diaphragm inside it has gone hard with age and it takes more pressure to operate the switch.

This doesn't sound fun to fix...

You would be surprised!

A socket is all you need to undo it. Top up you master cylinder first as you will lose a little fluid. Unscrew the old one, screw up the new one, and let the fluid flow around the switch a little as it goes back in, this will exclude nearly all the air for you. With a little luck you won't need to bleed the brakes

What? Something easy to fix on a mini? You learn something new everyday shame that pesky engine is in the way of the nut.

I'm contemplating doing the pedal box conversion - where you use the mechanical switch, but THAT doesn't look fun to do either

What? Something easy to fix on a mini? You learn something new everyday shame that pesky engine is in the way of the nut.

I'm contemplating doing the pedal box conversion - where you use the mechanical switch, but THAT doesn't look fun to do either

Took me 20min and cost $10.
$9 Toyota brake light switch and $1 angle from bunnings.
2 self tapping screws and i was able to use the existing wiring.

There was a time when the "new" hydraulic switches were poor quality and not lasting long.

Any updates of experience on where to buy a decent quality one?

Same thing here. Hydraulic switch was slow to activate and took a lot of foot pressure, so I replaced it with a mechanical switch on the pedal bracket. Used a right hand drill extension to put a hole through the bracket to bolt a switch to.

Original Mini brake lights, like I have on my van, are small and inconspicuous at the best of times by today's standards. Clubman type are marginally better. Don't particulary like high level back window led brake lights on a Mini, they may be functional but they just look so out of place on a classic.