Thanks for the advice marty,is jb weld available at bunnings? pretty sure i will be needing some,i'm thinking maybe fill the whole hole up with it and redrill the post after a few days give it time to set,just depends if it can be drilled,what do you think marty is it worth a try. ben

JB Weld is used to fill holes in engine blocks as well as many other applications.  It definitely can be sanded and drilled.  In this weather I'd allow 48 hrs for it to set properly.

Not sure if its available at Bunnings.  I bought my last lot on eBay.

It sets a dark grey colour, but I'm pretty sure you could paint it afterwards (ie a wood colour) and you would get it looking sweet.