The brake bleed nipple sizes that Andy quoted are the thread sizes not the across the flats spanner sizes. I think that the bleed nipple spanner size you require will be 11mm front and 8mm rear, those are the sizes for the ABV's fitted on my car at least. You will maybe make bleeding the brakes a simpler operation in the future if you fit ABV nipples at the same time. Info for them is also in the Alternative Parts List.
| 
