I wouldn't bother with another plastic one, it's destined to fail again. I'm planning to budget for an Ali one , seems once fitted you can forget it plus they are more effective at cooling..
+1
Go for the Mulfab fix. Clearly a design flaw with so many folk wt same problem. I changed for Al radiator and do not regret it. The plastic rad is not cheap either, I recall.
BertR