The firm now has planning permission to build 43 houses, 23 flats, a 1,000 sq ft retail or cafe unit and a public park.
And supermarket giant Tesco is set to create 30 jobs by opening a new 4,113sq ft Express store at the site.
OS’s former headquarters at the site was knocked down in 2012 as the firm moved to a new base at Adanac Park.
Work is already under way on the other two sections of the site. Barratt Homes is building 141 homes on its southern side, while Taylor Wimpey is building 179 homes on its northern side.
Construction work at the 24-acre site is set to be completed by the end of next year.