There don't appear to be any Calldoes locally in Kent (not one) from what I can see but that doesn't mean it isn't.
The first letter is the most problematic I agree. There is a capital B but this doesnt look the same as the mystery letter...
Calldar looks possible and there are a few Calldars in the next door parish of Wye. I think it might well be Calldar (a name I've never hear of but which clearly exists in Wye, Kent). I suspect this is a corruption of Coulter.
Richard Caldar married Elyzabeth Dod 1617 Oct 15 Wye.
This is probably our man. Many thanks as ever for all these really helpful suggestions.