Broken Odometer
 

What should I do if my odometer doesn't work? Should I just look up how far everything is before I actually leave to go there?

You can use a GPS... but really, you should get your odo fixed.

Also a ScanGauge has MPH but you have to cal it with a GPS. But I agree with Stouts, get your odo fixed.

Forgive me if i'm wrong, but is a working odometer not vital for a valid MOT certificate?

You can probably find a gauge cluster with a working odo in it pretty cheap in the junk yard.

If you can afford a GPS, you can probably afford to get a working used/junked odo/cluster installed.

get the gear kit from https://www.odometergears.com/bmw.html. you'll have to check to see if you have a vdo or motometer instruments, and it might help if you pull your instruments and the tach to verify that you're ordering the correct gears.

i've been through this on both BMWs that I've bought - the gears WILL break. even if you somehow find instruments with working original gears, they won't last long, and it'll throw off your car's odometer reading. buying new gears is the only reasonable way to go, even if it's a bit pricey.