All we know about this pub is a single newspaper report:

To be sold by auction, Lot 1: The freehold beer house, known as the Stag, (formerly the Bantam Cock), with old established bake house, Chaise house, and outbuildings, situated in Carr Street, Ipswich, now let to Mr Sidgwick.Ipswich Journal, May 1870**

The 1871 and 1881 censuses list John K Sidgwick as a wine & spirit merchant at North Hill House, Ivry Street. This may be the same person referred to in the above article, but it is not the pub.