The mint reading NICOL for Lincoln as seen on other issues isn't recorded by Allen, so it's likely that the moneyer is NICOL(E), which would be supported by the initial cross at 6 o'clock. He is recorded as working at Gloucester, Ipswich and Norwich. For Gloucester, it isn't Allen 277, but could be 276 (not illustrated). For Ipswich, all the legends showing the end of the name terminate in an E, so given it looks like the stop of a colon after L, would eliminate Ipswich if the signature is consistent. Norwich could be 663 or 664, but the Allen image is flat in all the parts where yours is struck up and vice versa. It isn't Norwich 665-668
In summary, it looks like one of 3 possibilities. Allen 276 at Gloucester and Norwich 663 or 664. The first two are bust A1 and the last A2, but some detail would have been useful! Sorry, can't do better.