Since then the design division has grown to 25 staff, bringing together the disciplines of architectural design, engineering and design-and-build co-ordination.
David McLean Design won RIBA accreditation last month.
Its director, architect John Caunce, claims that this will put the division "on a different professional plane".
He added: "The group is forging ahead with negotiated partnering agreements and prime contracting for big clients such as Barclays and Halifax banks and Shell service stations."