Sleeve

Our guest toilet was leaking, on the side of the drainpipe. Or perhaps, where the flush water comes in.
I removed the bowl and looked at both the sockets. I took measurements and went to the hardware store.
Unfortunately, the two nearby hardware stores only had more modern connections; our toilet is from 1887 1987. Obviously too old.
I couldn't find anything online either, so I'll probably need a specialist :(
Thanks to Incredibish for hosting the Tiny Tuesday challenge this month.