What size are the rear spokes?

[Mussels]

I rather urgently need to order new spokes for the back wheel, does anyone know what I need to order?
Wisper 905se

[Mussels]

Emergency is over as the retailer has some in stock, I'm still interested to know what they are though.
I found the shop China website which said they were 13g, if that's the British guage then it explains why I can't find a spoke spanner to fit - they all seem too small.