RAK Geberit leaking into pan

[Hammer time]

Hi

I have a patently quite old RAK slimline cistern and aged Geberit flush and fill assemblies, and one of these is leaking permanently into the pan. Occasionally causing the fill to trigger too.

I don't know which part to replace and assume (due to the fact I have a newer model of the same in the downstairs loo with different components) that whatever it was has probably been discontinued by now

My questions then, which bit is faulty, can I fix it or is it a swap out, what parts do I need and is it going to test my competency

I checked out a couple of similar posts but they don't quite tell me what I need (or I need more confirmation please)

Thank you in advance

 

[terryplumb]

Can't tell for certain from your pics ,but it seems that the water level is reaching the spillover point of the overflow tube ,is it ??
If it is ,the float valve needs adjusting ,or possibly replacing as it's letting too much water into the cistern.
If water isn't going down the overflow ,and water level in cistern is ok ,then the flush valve seal is probably letting by.

 

[Hammer time]

Thanks for your reply.
It's not the overflow but searching other posts I'm guessing it could be tiny bubbles in the seal as it seems to be a problem with these units whether it's the Geberit 230, 240 or 260 which mine appears to be.
I'll isolate the cistern and give it a look this weekend and get popping bubbles if I find any

 

[Hammer time]

... and, it's fixed. With a sharp knife to pop two large bubbles. Now I'm worried about the stop cock dripping black :/