I would recommend contacting the manufacturer, they may be able to replace it for you. Otherwise it might be worth joining slow cooking recipe groups on facebook and asking if anyone has a spare one. good luck and Merry Christmas
I didn't realise they weren't but to be honest after a good long cooking time in it, it's best to hand wash anyway as sometimes there is a residue left where the food level was and it needs to be scrubbed. I used to put my old one in the dishwasher and there was no problem with it.
Yes whole legs of lamb with bone in and one table spoon of liquid is sufficient or vodka if you like something different. The meat becomes very tender and the bone can be removed easily once cooked. Might be worth investing in a cook book that has many slow cook recipes for meat on the bone