PRECIOUS-Gold rebounds from 6-week low as dollar sags before Fed speeches

* Market sceptical of Fed's hawkish message * Yellen, Harker due to speak in London on Tuesday * Platinum recovers from six-week lows reached on Monday (Recasts, updates prices, adds quote/details; changes dateline) By Maytaal Angel LONDON, June 27 (Reuters) - Gold rose on Tuesday after hitting a six-week low in the previous session as bargain hunting set in and the dollar fell before speeches by U.S. Federal Reserve officials. Fed officials have signalled that they pla