Necro'd thread but I want too, only because I have another issue (unrelated) - but wanted to give closure to this issue. The radiator cracked/split between the ally housing and plastic side tank (Funnily enough a common issue I found from this forum) I replaced the radiator and upper/lower hoses (from Repco) and it's been great. So hopefully if someone is facing a similar situation they can see this, also in my OP about the filler neck damage - yeah there's been no issue. I installed a new cap with some tap grease and leave it a 1/4 turn undone. Has been that way since my OP and has been fine, I didn't try to fill the gouges as honestly, they are at best 2mm deep. Everything in that regard has been fine.