Coupling trouble!

[OlTallGuy]

Hi there. Just took delivery of new N gauge Ivatt 2MT 2-6-0. While fitting the DCC decoder in the tender, I accidentally dislodged the tender rear coupling, the usual Rapido type. Can't seem to get it back in position so it works properly. Big fingers and bad eyes really don't help of course! Anyone got any tips on this? Or know how it should be seated? Any help gratefully received!