(ShareCast News) - FTSE 250 finished lower alongside its blue-chip sibling as Brexit fears acted as a dead-weight on sentiment and trade, but served to boost the appeal and price of safe-haven gold.Aveva was ahead almost 10% as it confirmed receiving a revised and conditional proposal from Schneider Electric SE to combine with that company's Software Business in exchange for new Aveva shares and a significant cash payment.The cash payment would be distributed to Aveva's current shareholders upon completion, it said, responding to media speculation about the proposed transaction.The potential deal, if consummated, would see Schneider Electric own a majority equity stake in the enlarged Aveva, which was intended to remain listed on the London Stock Exchange.Also on the front foot was Centamin after founder and executive chairman Josef El-Raghy sold 5m shares not long after they hit their highest levels for five years, pocketing £5.5m.Meantime, shares in G4S slumped almost 5% after it emerged the security services company employed Omar Mateen, the suspect responsible for a mass shooting at the Pulse gay nightclub in Orlando, Florida where at least 50 people were killed.Mateen, who has been identified by state police as the gunman, was confirmed by G4S as an employee since September 2007. The 26-year-old worked as security guard for G4S in Florida,Trade has been affected by the looming UK vote on whether to stay in the European Union after 23 June.Wagering outfit Betfair said today that the implied probability of Britain voting to stay in the EU fell to as low as 64 percent, down about 14 percentage points from last Thursday when the probability was 78 percent.The ORB poll for the Independent showed 55.0% said they were now backing the option to leave the EU, against 45.0% who said they were supporting 'Remain'.A poll by the Financial Times showed 'Leave' has taken the lead for the first time, at 46% versus the Remain camp's 44%.At 17:05 BST, safe-haven gold was ahead 0.94% to $1287.90 an ounce, while copper was ahead 1.06% to $205.20 a pound.The price of crude hovered around the $50 a barrel mark, with West Texas Intermediate down 0.47% to $48.84 and Brent down 0.44% to $50.32.Market MoversFTSE 250 (MCX) 16,619.80 -1.23%FTSE 250 - RisersAveva Group (AVV) 1,854.50p 9.67%Centamin (DI) (CEY) 113.70p 3.36%Petrofac Ltd. (PFC) 730.00p 0.62%Beazley (BEZ) 356.00p 0.56%Millennium & Copthorne Hotels (MLC) 421.30p 0.55%Debenhams (DEB) 69.75p 0.50%Victrex plc (VCT) 1,419.00p 0.50%Acacia Mining (ACA) 346.40p 0.49%GCP Infrastructure Investments Ltd (GCP) 120.00p 0.33%John Laing Group (JLG) 215.50p 0.33%FTSE 250 - FallersOcado Group (OCDO) 226.00p -7.38%Allied Minds (ALM) 326.20p -6.80%International Personal Finance (IPF) 267.10p -5.32%G4S (GFS) 178.40p -4.80%Supergroup (SGP) 1,400.00p -4.63%Paysafe Group (PAYS) 374.50p -3.97%Kaz Minerals (KAZ) 142.30p -3.72%Evraz (EVR) 121.70p -3.72%Cranswick (CWK) 2,231.00p -3.50%Amec Foster Wheeler (AMFW) 426.30p -3.36%