Ah, I just found the code in the x_settings table in the database. There is a cgi_handler row that contains the cgi code block that has been causing my problems. The row was flagged as not user editable which is why I couldn't see it in zPanel. I have removed the code from the dabase but left the table row in place, just in case. This has solved my problem. I can only guess that this is a hangover from problems we had some time ago when we missed a zPanel upgrade and had problems catching up.
Anyway, many many thanks for your help - you pointed me in exactly the right direction!
Cliff
Anyway, many many thanks for your help - you pointed me in exactly the right direction!
Cliff