The Orange Balloon restaurant in Twickenham, Middlesex, has reopened after being shut for two weeks.
A spokesman for the group said the outlet, which only opened last December, had been closed for a refit and extension, adding 20 seats to the original 75.
The chain, run by catering entrepreneur Jerry Brand and chef Brian Turner, currently has two restaurants, the other being in Tonbridge, Kent. Two further 100-seat branches will open on 12 and 19 June in Hertford and Berkhamsted, both in Hertfordshire.
The Berkhamsted restaurant was originally scheduled to open in March and Brand had claimed he would have six outlets by Easter.