Thanks to IrishRovr and NormandieGirl for their time and effort in answering my question about leaving luggage at Caen train station. I'm very thankful they have not yet tired of answering the same question time and again as I've just now seen their answers to the same question on other posts. oops, sorry guys.
So I will now also share what they have told me and others before me.
According to SNCF website only some Paris metro stations have a left luggage facility, NOT Caen NOT Bayeux. This is because of security concerns.
Bit of a bother but what can you do ???