Special spanner for mainshaft nut - overdrive fitting

[MisterC]

Does anyone in the Newport Pagnell/Milton Keynes area have special spanner 600300 I could borrow?  I need it to remove/refit the castellated mainshaft nut when I (attempt) to fit my overdrive.  I haven't got any serious power tools or welding kit, so I can't fabricate one myself.  Or does anyone know of a tip to get it off without this scarlet pimpernel of land rover tools?  Thanks in advance.

[dave_2A_2.25Turbo]

.........erm, I managed with a Brass drift and a hammer. (What torque?...that'll be two more taps then...) :D  :oops:

[MisterC]

Managed it with a borrowed home made tool (scaffold pipe with nails welded in, worked really well actually).  A few well aimed drift/hammer blows were also employed!