UK's Convatec shares climb on new $300 million share buyback
** Shares of British medical equipment maker Convatec CTEC.L rise 5.45% to 243.8 pence ** Stock top pct gainer in FTSE 100 .FTSE index ** Co announces $300 million share buyback programme ** YTD, CTEC shares up 4.5%, compared with a 4.8% rise in FTSE (Reporting by Unnamalai L in Bengaluru) ((Unnamalai.L@thomsonreuters.com;))