I bought mine here in Australia.
The Openbuilds store keeps them over there.
Thrust bearing
https://openbuildspartstore.com/thrust-bearing/
Tension nut
https://openbuildspartstore.com/tension-nut/
The only problems will be if your lead screws are cut to close lengths and if the stepper motor drive coupling is very close to the end plate
You need about an extra 30-40mm in lead screw length and I had to step my stepper motors further away using 9mm spacers - see photos.
All up I needed 3 longer lead screws plus 6 sets of washers and nuts - cost about $AU150