Thankyou for all these replys, and of course, any more greatly appreciated.
On another point, chuckey, you kindly described that you used a 50mF capacitor at 24V.
I have also emailed yourself about this, as i would be most grateful to know how you charged up the 50mF?, especially if it was charged up by an isolated offline PSU....because just about every pesky offline PWM controller these days comes with built in "auto-restart", which shuts down the chip before such big secondary caps get charged up.
(basically , the modern PWM chips "think" that the big secondary cap is an overload on the secondary, and so shut themselves down)