UK's Travis Perkins rallies, SIG tumbles as CEO switches firms
** Travis Perkins TPK.L jumps 5.3% to 614p after naming SIG SHI.L chief Gavin Slark as next CEO ** SIG drops 8% to 16.5p as Slark plans to step down by Dec. 31, join Travis Perkins no later than Jan. 1 ** RBC says the hire removes uncertainty at Travis Perkins ** YTD, TPK down ~20% and SIG up ~12.5% (Reporting by Judes Joseph in Bengaluru) ((judes.joseph@thomsonreuters.com;))