Hi.
Problem solved!
OMG! So happy!
Called lexus today and they wanted £680 for all tappets...
this afternoon I left my car for my mechanic to start the project... he took out 2 belts aaannndddd... start the engine to eliminate faulty bearings...
no noise...
after inspection we found a few stones inside one of the belts... :D
that was my clicking tapping noise!
all good all fine guys!
(still we love big L)
:D