After apparent coolant leak, garage have found radiator has a leak. Stop leak put in for now but want to change radiator. Can't find which brand is OEM and autodoc have several options. What is recommended usually please?

denso nissens if want proper decent.
nrf not bad if want balance cost a bit .
don't buy cheap options as they generally garbage and many times leak straight out the box or fittings snapped off / poor fit .

Thank you, the two in the images below definitely correct fit for 3.0 H6? Thank you.

I've bought the Denso one, just waiting to get fitted.