Thanks for your reply. It was most helpful in getting to the answer.
I guess I am not using the Switch class in the way the framework authors intended (too many years with MFC I guess and I'm too lazy to learn how to position two 'Radio Buttons' of a Switch group in widely differing places in a tab control, so I'm using two separate Switch controls connected by code).
The control is a single 'Radio Button', i.e. not part of a group therefore assigning 1 doesnt work, however assigning 0 does 'check' it (put the dot in the circle) and mySwitchObject <<= Null; 'unchecks' it.
int s = mySwitchObject; returns 0 if 'checked', i.e. got a dot in the circle, and -2147483648 (0x80000000) if not 'checked', i.e. no dot in the circle. So I have an odd looking but effective way of achieving what I want to do.