Lucas 128sa ignition switch

i have this ignition barrel for a 110 I'm trying to rebuild.
The connections are as follows. From the 12o clock position
1. Large connector
2. Small connector
5. Large connector
4. Small connector
3. Small connector
2. Small connector

The cables I have are
Large brown
Large white
Small white red
Small white orange.

As usual all help appreciated

Lucas 128SA 35670 Key Switch. 4 Position switch.
1.Off
2.Aux
3.Aux/Heater
4.Aux/Heater/Start

Positions 3 and 4 are sprung loaded, so that when released the key will return to position 2. Connection by 6.3mm and 9.5mm spade terminals. Will fit either 19.6mm hole or 16mm hole (stepped mounting)

Large brown - battery feed
Large brown/red - heaters (engine, not the cab )
White - 'ignition' fed circuits
White/red - starter
White/orange - "accessory" (ie radio etc)

You should be able to work out with a test lamp or meter which is which.
Turn key to first position, ONE big terminal will connect to two small ones - which will be ignition and accessory.
Turn key to second position ("heat", against a spring), the other large terminal should become 'live' and I think ONE of the smaller ones will no longer be (that is accessory).
Turn key to third position ("start", also against a spring) and you should have another small terminal live (that's the starter).

Looking at it from another viewpoint :
The 'ignition' circuit should be live in positions 1, 2, and 3
The heater circuit should be live in positions 2 and 3
The starter circuit should be live in position 3
The accessory circuit should be live in position 1, but could well be off in positions 2 and 3