Windscreen wiper arm nut size?

[cdt]

Does anyone know the size of the nut at the bottom of the windscreen wiper arm?

Looks like it is probably a 13 or 14mm as these spanners in my collection seem to have gone walkabout, and the 12 doesn't fit.

Thanks.

[wedg1e]

13mm is as near as dammit 1/2"... or it could be 9/16" which is roughly 14mm.

Hope this helps....