Adding an extra leaf on mk3 rear springs

[vana mana]

I've had no luck at all finding a decent heavy duty set of secondhand rear leaf springs for my transit Mk3 160 model
So someone told me to buy a set of mk5 and trim a leaf down and add but with longer u bolts ?

Will this work ?

Anyone with info or ideas please as I can't afford to pay £400 plus to a spring manufacturer

Thank you