Johnstone render

We have been dealing with a rep for Johnstones who isn't too clued up on what he is selling so I thought I'd ask on here.

I've a job that needs doing in a scratched finish at 10mm beads, Johnstone say they guarantee for this but I wanted to ask on here does anyone know if the key coat primer is any good, I'd it similar to R-10 or is it just a base coat similar to hp12/x
It's going over brick and K-rend had said we could 2x r-10 then go on top but only with 15mm beads
Thanks