Thanks to Martin for this info:-
Apparently, the S-Cargo radiator is unique and cannot be easily changed for other than an original part. Mine started leaking and despite dosings of 'Bar Leaks' or whatever had obviously given up the ghost, spltting along the top (plastic) seam..

Enquiries through Nissan and other specialist Pike traders revealed that a new radiator would be £700 or so! One company suggested having one made, so I trawled through the local Yellow pages and found a company that would make one for me.

I took the old one out: pretty easy for an engineering type and delivered it to a chap who in turn took it to the company where he works. One day later, he'd fitted a new core (the middle bit with all the holes), re-used the lower manifold and furnished a complete new soldered brass top. The radiator came back cleaned and sprayed ready for re-fitting. £150 including VAT. Quite a price but a big saving over the original and the chap reckoned his was a better radiator with improved cooling properties.

I fitted it yesterday and it all looks good.

Contact me through David if you have the same problem.

Martin Ripley S-Cargo 'B azil' G21 BGS Swindon