Where does the rubber washer go on a Twyfords toilet handle?

I am about to replace the toilet handle on my old Twyfords Jupiter unit. The old one is fitted with a plastic bracket that has fallen apart and will all be cut off. The new handle has a brass bracket to hold it to the cistern. They supply a new bolt with dome head, a brass washer and a similar diameter rubber washer and the nut. No instructions of course... so would you put the rubber washer on the outside of the cistern, between bolt head and cistern - or on the inside. If inside would it go betweeen handle bracket and cistern or between the metal washer (with nut and handle ?

Thanks for any pointers

John

I am trying to find a Twyfords Jupiter toilet handle but with no luck so far. Could you let me know where you got yours from?

Many Thanks,

Ken