ER20-T2 Collet Spanner

I need a source for a ER20-T2 style collet spanner for the spindle on a Boxford A3HSRmi2 router.

It seems everyone normally sells ER20 collets with a hex nut but this spindle has a castellated one fitted. It's 35mm in diameter in case that makes a difference.

I do wonder if it would be easier to change the nut...

Adrian.

http://www.arceurotrade.co.uk/Catalo...t-Nut-Wrenches ?

http://www.ebay.co.uk/itm/ER20-colle...dgC9XfxR3KwIHw

ArcEuro's spanners start at ER25 :-(

Bought one of them - they're ER20 "Mini", so only 26mm across - the nut's 35mm diameter :-(

I've drawn a blank on the spanner front so have bought a new collect nut instead :sorrow: