I had tagged this on at end of previous threat ... but thought I promote it to its own thread as it may have been missed.
tried Googling and can only find them made up in cables by CTEK
I could then change the connectors on my RING charger to CTEK type and at least then have standard connections.
Accept a solution is to buy the extension lead and the 56-689 adapter .... but together these would be £18 ... pretty pricey.
Asked CTEK ... they just point me to accessory leads.