Mouchel has appointed its third group finance director in as many years.
Paul Rayner joined the now privately owned engineering consultancy last month, replacing Rod Harris.
Mr Rayner was previously at Chemring, which manufactures defence equipment such as munitions and counter-IEDs.
He spent 12 years at the business, which trebled in size since 2008 through organic and acquisitive growth.
Before this, Mr Rayner spent 10 years at business advisory firm Deloitte.
Mr Harris, a former finance director of Carillion Business Services, had worked closely with chief executive Grant Rumbles on the restructuring, delisting and management buyout of Mouchel.
Mr Rumbles joined the firm in October 2011 after the resignation of Richard Cuthbert.
Mr Harris had succeeded David Tilston as group finance director in June 2011. Mr Tilston had joined in August 2010, taking over from Kevin Young, who left the company after 12 years.
Mouchel declined to comment on the appointment of the new group FD.
The consultancy this week acquired infrastructure support services company Enterprise’s 50 per cent shareholding joint venture EnterpriseMouchel.
EnterpriseMouchel had a £210 million turnover in the 2012 financial year and recorded a 30 per cent rise in operating profit to £11.2m.
It won a place on Transport for London’s £2.6bn area-based joint highways contracts framework in November last year.
In August 2012, Mr Rumbles revealed a bank buyout plan that would return 1p per share to Mouchel shareholders and a delisting from the Stock Exchange.
Mouchel was passed to administrators, then sold to banks and the management team. It saw £87m of debt wiped out.
That followed an extensive restructure when it closed 13 offices.