Chief executive Fred Maguire said other factors for the improvement were a training scheme and the development of a call centre.
“We decided to trace as many as possible of our 'lost' sales or aftersales customers from the call centre,” he said. “We had a success rate of up to 40% at the first six dealerships where the call centre worked on the database.”
Mr Maguire said the group was expanding its Liverpool-based call centre which employed 20 people.
In its half-year results, Lookers recorded a 25% rise in sales (excluding Northern Ireland) compared with a national increase of 2%.
Turnover in the six months totalled £297.8m with an operating profit of £6.5m. Pre-tax profit was £5.029m. Craig McKinney, Lookers chairman, said: “The result is particularly pleasing in the light of widespread reports that the retail customer is dead.”
Lookers' Rover outlets moved from “significant losses” to a small profit and there were strong performances by Land Rover and Audi, he said.