I need a Wirquin toilet cistern spare part?

About 11 years ago, I bought a dual flush WIRQIN toilet cistern - concealed - possibly type MALIN, but the pipe sizes do not match.

Recently, there was water leakage at the bottom of the cistern where water enters a 49 mm outer diameter vertical pipe, turning through 90 degrees to a 39 mm outer diameter pipe which enters the toilet. I discovered that no seal had been installed - instead the fitting/outlet pipe had been bonded/glued into position - and this connection had failed.

Please advise how I can obtain a new seal. Thank you - I have looked at various web sites but cannot find a relevant drawing or parts list.

Examining the installation, there does not seem to be a secure method of retaining the outlet pipe in position. How is this security is supposed to be achieved? Unlike BASIC and ELEGANCE, 2 screwed/threaded studs are not fitted to secure the outlet pipe/seal.

My address is
183 Cavendish Avenue,
Ealing,
London,
W13 0JZ
England.

contact trevors83@hotmail.com