Marshall Motor Group has acquired Lisles Motor Repair business for an undisclosed sum.

The move will see Marshall gain three Vauxhall sites in Knebworth, Hitchin and Welwyn Garden City, as well as a separate Alfa Romeo showroom at the Hitchin facility.

The sites, all of which have retained the same staff, will be managed by managing director Peter Campbell, previously franchise manager of Marshall Chrysler Jeep and Dodge in Cambridge.

“We have been looking to build on our successful relationship with Vauxhall for some time and this was the perfect opportunity for us,” said Roger Knight, chief executive of Marshall Motor Group. “The territory covered by these new sites fits well with our existing markets and this will also increase career development opportunities for our employees.”

Marshall Motor Group represents 16 franchises from 43 sites, with 1,700 employees. Last year it reported a turnover of £450m.

Christopher Walkinshaw, a spokesman for Marshall, said the group would be looking to grow this. “The main thing is to develop the Vauxhall franchise and grow within our existing territory, though we’re always looking for appropriate opportunities that fit in with our growth strategy.”

Lisles was a family-owned business founded in 1900 by William Lisles and sold to Stanley Deards in 1937. It had represented Vauxhall since 1948 and until recently had held the Fiat franchise for 30 years.