Hi wittaj and Alistair
Thank you for your replies.
wittaj - your solution is a good one but at $106 Australian it doesn't make it a worthwhile proposition.
Alistair - Unfortunately it doesn't have that facility.
I have already replaced these three cameras with new types but it seemed such a waste to have them sitting around. They work fine in daylight but poor when the IR is needed.
I guess I will find an application where the IR is not required.
Thank you once again for your responses.