A quick search via google returns one reference, in a newspaper report, to "the Taunton Carol, sub-titled A Lovely Lady Sat and Sang". That would be the first line, then. Try The Virgin and Child, and see if that is what you are looking for.

The carol appeared in Christmas Carols New and Old (Bramley and Stainer, 1871), the whole of which can be seen in facsimile via this link. I don't know what the connection with Taunton might be.