I would try (if can afford) to buy 2 boards, one for surfing & one for kiting.
The difference between a good board for surfing & a good board for kiting is large.
Theres a number of reasons why you should
try to get specific boards for kiting & surfing....heres a few.
Like a lot of the guys have already said a small fish like board (kite specific) is awesome for Perth kiting - theyre right!!! Now, your not really going to have alot of joy trying to surf this due to its small volume and considerably heavier weight (for strength).
For surfing, especially when learning you require a board with considerable more volume than you need for kiting (for paddling reasons & ease to catch wave). Surf boards are awesome when nice & light in weight... Now this lightness means its not cut out to be repeatedly bashed around bouncing over chop etc. If you do use your "nice & light" surfboard out there the constant bashing around is going to stuff your board for surfing. It will lose its shape slightly, get pressure dinged & lose its performance.
...Now we're moving into surfing season perhaps concentrate on buying yourself a surfboard ideal for learning to surf.
Save your cash through the winter & towards the kiting season then buy an awesome new kite surfing fish.
Having a board that suits what its designed for really does help, it makes being out there so much more successful (in progressing) & so much more fun!
If you really want a board to kite surf through winter, buy a cheapy to begin with & leave your surfboard just for surfing if possible. Decent surfboards designed for surfing just dont cope well with the thrashing of kite surfing.
Enjoy