Hey Viffer,
I pretty much always hit the pool at Brighton - was driving there so much I somehow convinced the girlfriend we needed to buy a house in Sandgate.
I reckon a bigger kite's the go. I picked up a 2nd hand 18m Naish X2 a while back for $300. They were a great model for their time (02/03) and I've had loads of fun with it - used it as my main kite when my 14 died. 18 is a good size for the lighter days at Brighton.
As a newb I'd say you should think about a 2nd hand kite, there's some bargains around and you'll put more damage on your kites in the 1st year than you will later on. Plus the longer you wait the better kites become - the technology is still progressing fast.
I've now added a Best 21 BFK to my collection, which will get me going happily in the 10-15kt range at 80kgs on a 122cm board. The BFK's are a great kite: powerful, stable in the air, light bar pressure, depowerable. There are some 2nd hand 18's around for about $500. They are 5 line only as they have a bridle, so you would need one with bar included if the Turbo Diesel's aren't.
Some people don't like the feel of big kites, mainly because they turn & accelerate slower... not to mention more pumping on the beach. Once you get used to the timing they have their advantages though. I call the BFK my 'park & ride' kite because one dive and I can generally let it go with just the occasional trim correction on the bar. Also the bigger the kite the more glide when you're coming down from a jump.. it's a nice feeling to land so softly, seems like you have to stretch your feet down to touch the water else you'll just hover a foot off it all day.
Anyway, just another opinion for you to think about