Replace 2 Broken Front Torsion Leaves or get a new set?

Been putting up with a cricked neck as we negotiate the ups & more rudely DOWNS of South London speed bumps but it's got to be sorted so should the leaves be replaced as a bundle (£200+) or would replacing just the 2 broken ones do?

 

I'd just replace the broken ones. Finding a full set can be difficult anyway.

 

Thanks. I've added a WANTED ad. Fingers crossed.

 

Which leaves are broken? Longies, shorties?

 

Err Toppie & Bottomie so narrowist