38 Seymour Street , London W1 Back Location: Mayfair Total Size 8,295 Sq Ft GN2 acted for the Portman Estate in advising on the refurbishment and marketing of this 8,300 square foot office building, which was their Headquarters from the 1950s. The building was ultimately leased to Bridges Ventures at £520,000 pa (£70 psf on best space) on a new 15 year lease with 15 months’ rent free in August 2014.