I have re-soldered the transformer, plugged it all back in and Hey presto, its working again.
Must have been the transformer solder joints that were the problem, in fact they didn't look as if they had been soldered very well and judging by the ease of which it came off, must have been dry joints.
Thanks to all for the help and assistance in pointing me in the right direction to solve the problem. Very helpful.
Must be a day of these as I’ve just had one to repair for someone , no life other than the switch is lit up , changed thermal cut off , light went out , but still no life , checked transformer and all is well , next I turned to the trigger , took torch apart and tried it and it worked - put it back together and dead again , very strange , so took it apart again pushed the contact over to the valve and it worked - then I noticed where the valve sits on the trigger side the plastic moulding was at a angle and stopped the contact from going all the way - trimmed it up and all is well again - bloke chuffed to bits