hi pescody,
built your circuit.
Tried a number of switches, found best results were with the 0.22microfarad
capacitor removed. Works every time.
Works ok for supplies from +5v thru +12v
At +9v with my LED, the LED draws 9 milliamp. [ nice and bright]
With the capacitor in circuit, using the scope to measure pin 11, the
slow rise time of the voltage at pin 11, when the switch was opened, caused
the device to go unstable. This is one of the problems with this type
of configuration. The 4013 requires a clean/fast rising clock edge to ensure correct operation.
Using a mechanical switch with 'bounce', which you then
try to filter out, using a resistor/capacitor filter, just 'masks' the problem.
I would suggest that you look at the dual invertor diagram that has been
posted.
Hope this helps.
Regards
EricG