G'day!

Vectra failed MoT due to broken nearside spring, so I got a spring and a guy is fitting it today.

Mechanic rings up and says it's the wrong spring, too short I phone motor factors place and they say that there's only the one spring listed.

What's up here?

I know folk say replace both springs but due to other circumstances it isn't possible financially at the minute and mechanic said just do the one that's broken.