I think the polo radiator will be fine, it seems thicker and the water channels look like they carry more coolant as they are thick tubes rather than small square tubes like the Clio.
I can always change it but for £30 it's worth a punt. I can't see the engine running too much warmer, my old one never did and having them side by side it only loses about 2" on the top.
Anyway, been in the garage tonight. Got the new thermostat and housing on as well as the top breather plate. Also had my silver VHT paint through so the head got a liberal coating as did the gearbox.
Also got my lightened flywheel back today which has had 2lbs taken off which is just under 1Kg. Still unsure if I'm going to use it or not as yet.
Anyway, pictures...
Also got the sump ready to come off for ARP bolts on Saturday, but will load engine up Friday night ready for Saturday then all going well it should be in Saturday evening!