The first office investment to come on the market this autumn, Twilfit House, at 137/140 Upper Abbey Street, Dublin 2, is likely to make in excess of £4 million when it is auctioned on September 23rd by Gunne Commercial. The 27,990 sq ft buildings is let to the State-agency FAS under a lease with 11 years to run. Stefan Foster of Gunne estimates that the present rent of £169,000 per annum - the equivalent of £6 per sq ft - should double at the next rent review in August, 1999. Twilfit House is close to the Jervis Centre and has redevelopment potential. The building is being sold for businessman Donal O'Mahony of building suppliers TJ O'Mahony. It was owned at one stage by property developer Phil Monahan.