SHARES in Frankie & Benny’s owner The Restaurant Group tumbled by 27 per cent after the company issued a profit warning and announced the immediate departure of its chief financial officer after 11 years with the company. The company posted a 2.7 per cent drop in like for sales and said that in the short term it did not anticipate any improvement to underlying trends. Full year like for like sales are expected to be down by as much as five per cent, leading to pre-tax profits of around £75 million, down from £86m.