Banbury, first recorded as living in Gloucester in 1378, was well established among the freemen of the borough by 1380, when he stood surety for one Robert Janus in the latter’s application for a licence to exercise his trade in the town. It was not, however, until 1389 that Banbury was made a bailiff. This, the only year in which he held civic office, was notable for a lengthy dispute over property between the commonalty and the priory of Llanthony by Gloucester, but this did not reach a climax until after Banbury had represented the borough in Parliament.
Banbury was both a merchant and a cloth manufacturer. So, too, was his namesake John Banbury II of Bristol, and it is sometimes difficult to distinguish between their trading activities, especially as the Gloucester man carried on at least part of his trade through Bristol. It was certainly he of Gloucester, however, who in February 1386 had obtained a royal licence to purchase 300 quarters of corn in Gloucestershire and Worcestershire for shipment overseas, the ordinances prohibiting the export of grain notwithstanding; and he was once again described as ‘merchant of Gloucester’ when, in June 1398, he took out a royal pardon. Banbury evidently developed close trading connexions with the wool merchants of Cirencester, one of whom was a debtor of his in the early years of the 15th century, and he went so far as to acquire shops and tenements there. Evidently his concerns prospered, and he became wealthy enough to be able (in association with Roger Ball) to advance Henry IV a loan of £100 towards the suppression of the rebellion in Wales.
Banbury made considerable investments in property both within and outside Gloucester. In 1384 he and his first wife had acquired 13 messuages, arable land, meadows and fishing rights in Longney (six miles from the town), and he was subsequently in possession of an estate at Horsemarling. He continued to add to his holdings in Gloucester itself, making substantial purchases in 1398 and 1402, which included those shops, houses and curtilages in Eastgate Street and Grace Lane which had previously belonged to Richard Baret.
By his will, drawn up at Gloucester on 23 June 1403, Banbury requested burial next to his first wife in the Greyfriars church, although he bequeathed £20 to his parish church of St. Michael for the provision of prayers there. The principal beneficiary was his son Thomas, who was also to inherit all the merchant’s property following the death of his mother (Banbury’s second wife, Joan). The latter, moreover, was to act as the boy’s guardian during his minority. In the event of Joan’s marrying again, however, the former Baret estate was to pass immediately to Thomas. Should he die childless, the lands were to devolve on Banbury’s daughter Alice for term of her life, and then to his executors, so that they might provide masses at certain hours of the day and night for his soul, those of his ancestors, and for the bailiffs of Gloucester. In the event of there being no further heirs, Banbury’s property was to be divided equally between St. Mary’s abbey at Cirencester, Llanthony priory, Gloucester, and St. Michael’s church. Young Thomas was to receive a large bequest of £200, it being stipulated that if he should die under age, half of this sum should go to the indigent poor of Gloucester, £50 towards repairing roads in the area, and the remainder towards the expenses of the marriages of local girls. The many other bequests included casks of wine, a white worsted gown (to the notary of Cirencester abbey), armour in the form of baselards and harness, silver vessels, a missal and a bible. A damask mattress, vestments made of gold cloth, and utensils from Banbury’s home were all left to Thomas. Banbury’s executors (his widow and William Archebaud of Cirencester), were given administration of the will on 29 July 1404, following probate on 10 June. Joan did in fact remarry, and in June 1407 she and her second husband, the lawyer Robert Gilbert II of Gloucester, conveyed her dower portion of Banbury’s estate in Gloucester, Cirencester, Horsemarling and Longney to her stepson.