Speedy acquired the site in 1994 but the removal of green belt restrictions from it in 2017 meant it became viable to develop.
Speedy gave the land had a book value of £100,000. The profit from the sale, after related costs, will be recognised as an exceptional item in its accounts for the year to 31st March 2020.
Speedy chief executive Russell Down said: "We are pleased to have completed the sale of this asset to a natural new owner in the shape of Bellway Homes Ltd. The disposal makes strategic and financial sense for Speedy and the proceeds will be used to benefit the core operations, in line with our capital allocation priorities."