I am little unclear which cable you require but from your photo you appear to showing showing fan requiring a PWM and ARGB connection. Without all the info this looks like it might be of help.
And I agree it doesn't look like overclockers have that cable for sale on their website at least.
I hope you get something sorted and agree its not fair for you to have to buy a complete new fan just to get the cable. Also Lian Li fans are far from the cheapest.Iis not just over clockers i cant find it full stop