It appears that riding a highly strung special, made of a variety of Italian marque's parts, through the winter is not conducive to long term reliability.
I'm pretty sure the pink stuff should only be inside the radiator....
Not worth considering a repair, eBay will hopefully come up with a replacement RSV4 radiator and then Matt Bennet at Saxon Motorsport can add the same brackets as before. I'll ask his advice about some form of coating or treatment that could stave off the inevitable corrosion.