Agreed. I was more interested in the inner workings and interchangability of keys, barrels, handles, and tumblers through the years. Since, i'd be purchasing the complete Mark 3 lockset. I've retumbled German cars and for many years, the actual tumblers are interchangable. The Mini is new to me. Thanks for the reply though. 

I have 3 keys for my Traveller. It's not a problem. How often do you open the boot, or the rear doors in my case?

Hello, first time poster and new to us 1970 Austin Cooper. It came only with ignition keys. They do not fit the door or boot. I'm not able to lock the doors or the boot. To complicate it, the car has Mark 3 door handles and a Mark 2 boot handle. I intend to purchase the kit to replace the MK3 door handle tumblers and found a good you tube video on how to remove the tumbler from the Mark3 handle without the key. 

The kit comes with a new boot handle tumbler to match the doors, but not sure how interchangeable the brass tumblers are. I imagine the complete Mark 3 tumbler will not fit the Mark 2 boot handle. Is this assumption correct? Next choice would be to rekey the Mark2 boot handle to match the new door handle key. Are the brass tumblers interchangable between model versions? 

I do have the option to purchase a new Mark 2 boot handle with key. I like the Mark 2 boot handle style and it should fit in, but now I have 3 different keys. 2 keys would be preferable. Any information from someone that has worked through this would be helpful. Otherwise, I'll update my post when I figure out a solution. Thank you. mark