Ralwigh did that with a lot of their mid to late 80's bikes. I have a USA built 88 Peak frame that goes the same way.
The XT brakes that came off it had special springs with both "tines" on the same side of the spring, if you get what I'm saying. Meaning, each end of the col that bends out perpendicular to the spring occurs 180 degrees from where they would on a standard brake spring.
As many brake manufacturers used different setups for these springs for different brakes, I's suggest heading doen to your local long-established bike shop and show them the springs you have, and tell them that you want the bendy bits to end 180 degrees different relative to one another than those you currently have.
If they're young and confused, ask them to point you to the big parts bin with the brake springs in it, and you can root through.