many thanks to Stav for your help, i managed to find a salvage replacement theft ecu with the right part no. , it cost me £80 but lexus wanted over £400 for a new one so not too bad, plugged in and hey presto, lights! all working perfectly. So what would have cost me at least £600 parts and labour from an electrician who wanted to take the front bumper off and take out the headlights to start with (i am doubtful that he would have ever found the real problem), cost me just £80 and a couple of hours fiddling which has given me some knowledge in-case the problem occurs again,
It is really good of you to share your expertise to help others, much appreciated!