Ocado rose to the top of the FTSE 250 Friday after the grocery website said it was well placed to take advantage of rapid growth in online sales. The company is currently in talks with Morrison to help the supermarket launch its first online shopping offering and said the deal would be complementary to its existing relationship with Waitrose.Mobile satellite company Inmarsat also advanced after announcing the acquisition of TC Communications, a Sydney based satellite communications specialist.Centamin, on the other hand, retreated after the Egypt-focused gold miner said an advisory body made unfavourable recommendations to the court that will decide the fate of its only operating mine Sukari.Lonmin tumbled as the recent plunge in gold prices continued to hit mining companies.FTSE 250 - RisersOcado Group (OCDO) 225.00p +7.86%Inmarsat (ISAT) 716.00p +6.87%Morgan Advance Materials (MGAM) 288.40p +6.07%BBA Aviation (BBA) 270.90p +3.83%Fenner (FENR) 378.20p +2.94%St. Modwen Properties (SMP) 294.00p +2.83%AZ Electronic Materials SA (DI) (AZEM) 303.20p +2.78%IP Group (IPO) 149.00p +2.55%Ashmore Group (ASHM) 420.80p +2.53%Laird (LRD) 208.20p +2.31%FTSE 250 - FallersCentamin (DI) (CEY) 37.95p -16.78%Lonmin (LMI) 276.50p -7.89%Hochschild Mining (HOC) 260.20p -4.58%F&C Asset Management (FCAM) 96.35p -4.41%United Drug (UDG) 327.40p -3.71%African Barrick Gold (ABG) 148.30p -3.14%Imagination Technologies Group (IMG) 306.00p -2.92%Petropavlovsk (POG) 147.40p -2.90%Provident Financial (PFG) 1,554.00p -2.88%Brewin Dolphin Holdings (BRW) 204.00p -2.39%RD