Got it at a vintage store in Victoria called Vintage Funk. Pretty cool place, lots of old interesting stuff of all kinds. They were having a clothing sale for 50% off so I got it for $60. Judging by eBay auctions I'm seeing it was a pretty good deal. Similar US Ike jackets cost less but the Commonwealth ones seem to go for more. Different materials/construction I think. Rarity may also be a factor, I'm sure US stuff is much more common in the market.
Cool that your family has your Grandfather's diary and photos.
I don't have much connection to any of the wars myself. My grandfather wanted to serve for the RCAF in WWII but being of German-speaking descent he was prohibited from doing so. Probably for the best, otherwise there's a chance I might not be here! But I'm really interested in everything historical, especially if it's local somehow and have always been fascinated with everything military since I was a kid.