Wall mounted pan leak at bottom

[Peterade]

I have an Opaz wall-mounted pan and have a leak at the bottom. Not from the concealed cistern but from the round hole at the bottom center of the pan.
This has been slowly developing over the months and is now a steady drip. I'm not sure of the purpose of the hole. The water level in the WC seems to slowly go down. Could there be a crack in the porcelain?
Thanks

 

[old duffer]

2 options for the water source (if you are certain its not the cistern)
Waste connection or a crack in the bowl
The hole would have been for the excess slip so follow that back and you have the waste connection.
put some really bright coloured food dye in the toilet. If the leak is coloured you have a crack, if its not you have a waste connection seal issue

 

[Peterade]

Thanks Mr Duffer,
Tried food dye and after a few hours some drips but no colour. What I can't understand is how the water is coming from the small
opening at the bottom of the bowl. It's not coming from where the WC joins the wall nor dribbling down that side but the very bottom of the WC.

 

[just pumps]

My understanding is that the hole is where they hang the pan from when they are dried and baked in the kiln.
Can you put food dye in the cistern, Im thinking the water is from the flush pipe.

 

[terryplumb]

Judging by the discoloured staining on the wall tile ,I would suspect the pan connector.

 

[Madrab]

If no coloured water from died pan then it can only be the either the pan connector or the flush pipe. Time to take the pan off the wall methinks.