Bodyshop group Baldwins has gained the BSI Kitemark at all its four sites.
The business, which has repair approvals from Honda, Mazda, MG, Mitsubishi, Nissan, Peugeot and Renault, claims the Kitemark is paying off.
It has bodyshops in Aylesbury, Corby, Stratford and London and repairs 11,000 cars a year.
Peter Randhawa, group general manager said: “The Kitemark has already helped us gain more business and we believe it is an efficient tool in gaining future business."
Randhawa said Baldwins is keen to expand further.