Ad blocker detected: Our website is made possible by displaying online advertisements to our visitors. Please consider supporting us by disabling your ad blocker on our website.
It looks like NB to me too. Unfortunately there are 2 London goldsmiths' registers missing, that for smallworkers from 1739 to 1758 and the largeworkers' register covering 1758 to 1773. It is quite likely that NB's mark and details were recorded in the largeworkers' register.