The diode repair thingy arrived today so I went out and did a bit of cutting and crimping.
The green/red and green/white wires from the warning light cluster which are feeds from the indictor switch need cutting and baring back.
One of these green/ wires then gets spliced into the earth wire (black). Seems counter-intuitive I know adding a live to an earth but there it is.
The other green/ wire joins the trio of wires on the repair doide thingy.
The remaining 2 wires on the diode thingy then go to the red/green and red/white wires to complete the circuit.
With about 10 volts in my slave battery I fired the flashers up and they worked perfectly and the dash flasher warning light looked brighter than Ive ever seen it

Thanks again for the advice on this especially Migwielder (Tony) I'm happy today

Tony