Group like-for-like sales for the 28 weeks to November 9 were up 2.2% from -0.3% in the first half with interim sales up 0.8%.
At its Somerfield stores like-for-like sales were up 1.9% from -0.7% and up 0.4% over the first half.
The Kwik Save fascias improved sales to 2.6% from 0.4% in the first quarter and by 1.3% over the half.
Maguire leaves the company after just two years following his move from T&S Stores and will be replaced by Robin Whitbread, currently group buying director, who will combine the role with that of md of the Kwik Save unit.
Last month, Somerfield warned on full-year profits and said chief executive Alan Smith was to depart, which wiped almost 50% off the supermarket’s share value on the day.
Somerfield also said that supply chain director Martin Oakes would join the board with “immediate effect”.
Executive chairman John von Spreckelsen noted that Oakes’ appointment reinforces the “critical importance of logistics and IT to the group’s retail strategy”.