Help needed to identify this hairy caterpillar

[Janit]

I hope someone out there can help me identify this caterpillar we spotted in the garden yesterday. The colours haven't come out very well as the photo was taken with mobile phone camera. The stripe down the back is yellow and the stripe down either side is white.
Anyone know what it is? I've never seen one with what looks like a dorsal fin before.

[Dogghound]

Its a Grey Dagger Acronicta psi

[Misanthrope]

I think it's a grey dagger moth caterpillar. (Acronicta psi)

[Janit]

Wow! That was a speedy reply. Thanks very much for that. I've been searching the net for hours with no joy but found loads now that I've put the name in.
Cheers.