OFFERS in excess of £1.5 million are being sought for St Helen's House, a large Georgian house overlooking the Stillorgan dual carriageway in Dublin after it failed to sell by tender. The house, which stands on almost 4.5 acres, has planning permission to be redeveloped as a 150-bedroom hotel. The planning provides for a four-storey extension and for the provision of a leisure centre. Gunne and Jones Lang Wootton are joint selling agents.