Thanks
It's a close coupled system and yes, someone has handily tiled right up to the cistern so you have to be a contortionist to access the connection between cistern and outlet.
Has anyone any ideas about how to connect up the flush (inside a toilet cistern) to the outlet into the toilet when the whole area is boxed in around the cistern and you can only just reach around to hand tighten the connector. It is of course leaking as I can't tighten it enough.