leaking close-coupled cistern

Is there room for a digital camera to take a flash photo? You'll probably have to use Macro mode.

Your header says close coupled cistern but you seem to refer to a low level cistern (that is a cistern separate from the bowl and connected by a short flush pipe). If it is low level then try to get a hand round the back where the pipe enters bowel and find out if the leak is coming from there (very likely). The pipe may have worked a bit loose and just needs pushing back into the connector.

Never a good idea :-) Mind you, I've found them boxed in & tiled over.

Soounds about right.

Hard to tell exactly where leaks like this actually start because the water runs along surfaces until it falls off & then appears in a different place.

Only three places it can leak; (a) where the siphon goes through the cistern base & is secured by a large nut underneath, (b) at the joint where the pipe connects to the thread on the bottom of the siphon, or (c) at the push fit finned connector at the back of the toilet bowl.

If it appears only to leak when flushed you can rule out (a).

Dry everything off with kitchen roll, flush & feel around for a leak.

My money is on (b).

Sounds like the cupboard is coming out :-)

OMG - what sort of flush does it do?

Mmmmmm that looks like the number 2 flush.