LONDON, Nov 19 (Reuters) - Reckitt Benckiser shares rose as much as 3.1 percent on Thursday on a report of a linkup with U.S. peer Colgate Palmolive, but analysts were sceptical over an immediate tie up between the two. A spokeswoman at the British household cleaning goods group had no comment on the media report, while Colgate's CEO Ian Cook also declined comment in an interview with Reuters ...