It was another subdued finish for London's stocks on Thursday as the market continued to fluctuate at a 15-year high on the back of mixed newsflow about Greece and uncertainty regarding global monetary policy.The FTSE 100 finished the session down just 0.1% at 6,888.90. The index has stayed broadly flat since closing at 6,898.13 on Tuesday, its highest finish since reaching an all-time closing high of 6,930.20 in December 1999.GreeceGreece on Thursday submitted a request for a six-month loan extension, but on different terms from the existing bailout. The Greek proposal reportedly asked for flexibility on the "current arrangement" and more help for the country's banks.However, Germany rejected the request, saying that Greece did not present a "substantive proposal for a solution"."Greece is running out of time and money," said Berenberg analyst Holger Schmieding. "Having already come part of the way, Greece may well move further and accept the current programme as the basis for all further discussions at the Eurogroup meeting Friday," he said.The European Central Bank on Wednesday granted Greece's banks €3.3bn in funds under its emergency liquidity assistance programme, though this was less than Athens had requested.Central banks in focusMinutes from the January Federal Open Market Committee meeting released on Wednesday showed that "many" members said a premature rate increase could be detrimental for the recovery, while "several" believed a later move could lead to high inflation.The European Central Bank (ECB) also released minutes of its latest meeting, during which it decided to introduce a €1trn quantitative easing package. This was the first time the ECB has revealed details of its meeting, which revealed that some members had voted against the stimulus package, which is due to start next month.Minutes from the Bank of England's policy meeting on Wednesday showed that while the vote to keep rates unchanged was unanimous, policymakers had different opinions on the timing of a rate hike given the recent deterioration in inflation.CentricaShares in Centrica dropped 8.5% after the British Gas owner slashed its dividend and future payout policy, and warned that earnings for next year will be lower than expected too.Oil and gas stocks such as Tullow, BG Group, Shell and BP were also under the weather as Brent crude prices fell 3.5%.BAE Systems erased earlier losses after predicting marginal growth in underlying earnings in 2015, as it eased worries about defence spending in the UK and painted a positive outlook for the US market.High street sportswear retailer Sports Direct impressed after saying it is confident of increasing profits this year despite a significant slowdown in sales growth in its third quarter.SABMiller edged higher despite the resignation of its chief financial officer Jamie Wilson for personal reasons. He will exit the board immediately and will officially leave the group on 31 March 2015.Petra Diamonds jumped after raising its production guidance from 3.2m to 3.3m carats for the 12 months to 30 June.Drinks packaging group Rexam rose after agreeing a £5.4bn takeover by US rival Ball Corporation, a much larger higher valuation than had been expected by the market. Market MoverstechMARK 3,133.18 +0.05%FTSE 100 6,888.90 -0.13%FTSE 250 17,049.79 +0.28%FTSE 100 - RisersRolls-Royce Holdings (RR.) 962.00p +2.94%easyJet (EZJ) 1,785.00p +2.12%Dixons Carphone (DC.) 441.60p +1.99%Associated British Foods (ABF) 3,057.00p +1.97%National Grid (NG.) 891.10p +1.96%International Consolidated Airlines Group SA (CDI) (IAG) 564.00p +1.90%Barratt Developments (BDEV) 496.60p +1.74%Sky (SKY) 956.00p +1.70%Persimmon (PSN) 1,709.00p +1.67%WPP (WPP) 1,506.00p +1.62%FTSE 100 - FallersCentrica (CNA) 257.10p -8.54%Babcock International Group (BAB) 996.00p -5.68%Anglo American (AAL) 1,223.00p -2.86%Tullow Oil (TLW) 398.20p -2.66%BG Group (BG.) 951.50p -2.58%Royal Dutch Shell 'A' (RDSA) 2,109.00p -2.09%Royal Dutch Shell 'B' (RDSB) 2,198.00p -2.07%Glencore (GLEN) 283.55p -2.04%GlaxoSmithKline (GSK) 1,526.50p -1.86%Weir Group (WEIR) 1,862.00p -1.74%FTSE 250 - RisersPetra Diamonds Ltd.(DI) (PDL) 188.90p +7.88%Rexam (REX) 569.50p +6.05%Home Retail Group (HOME) 208.00p +3.79%Diploma (DPLM) 785.00p +3.63%Dignity (DTY) 1,960.00p +3.54%Euromoney Institutional Investor (ERM) 1,042.00p +3.17%Just Retirement Group (JRG) 144.10p +3.15%Galliford Try (GFRD) 1,464.00p +3.10%Vesuvius (VSVS) 478.00p +3.08%Entertainment One Limited (ETO) 296.20p +3.03%FTSE 250 - FallersPremier Oil (PMO) 175.00p -4.94%Hunting (HTG) 488.30p -4.63%Bank of Georgia Holdings (BGEO) 2,140.00p -4.51%Afren (AFR) 10.61p -4.41%Soco International (SIA) 289.20p -4.21%Catlin Group Ltd. (CGL) 677.00p -4.04%Drax Group (DRX) 403.10p -3.43%Cairn Energy (CNE) 197.70p -2.90%Ophir Energy (OPHR) 141.90p -2.87%Countrywide (CWD) 522.50p -2.79%