Crikey that takes me back a few years, only thing I can advise is clap like mad when they do something in the potty and leave them to run around in the house with no nappy then a quick move to the potty if you spot something happening
Then when they have used it take them up to the toilet and show them where it goes, then flush.... when they are using it regularly have another potty by the toilet and get them used to going in the bathroom to use it...gradually progressing to using the loo
Good luck,
