Photos attached. The metal sleeve for the float is corroded through, I assume this is not reparable. My understanding is that this is from an early model and replacement is with a different style. Is it just a straight replacement for the ‘newer’ style insert that are available?

 

Also replaces C16177. You already have the newer polythene bottle.

 

Grey rubber cap finishes the job nicely.

 

Hello RMerkley, as a precautionary measure, remove the dust boot on the master cylinder on the inside of the car and inspect the cylinder for brake fluid leaks and corrosion, many of the cars are running aluminum master cylinders, and if it's cast iron, it probably needs sleeving too if the shield in the reservoir is that bad.

 

If the shroud on the brake fluid level indicator is that corroded, like Jeff I would be decidedly worried about the condition of the rest of the braking system. Brake fluid is hygroscopic (absorbs water) and should be completely changed out every 2 years. If not this leads to a drop in boiling point which can lead to brake failure if the fluid boils & cause corrosion in the master cylinder & all brake calipers.