Renishaw was a high riser after UBS upgraded the precision tool maker from neutral to buy, saying that the long-term story outweighs near-term risks. Oilfield support services provider Hunting followed suit, rising 4% after saying results for 2011 are set to be above market expectations after a strong finish to the year. Meanwhile, oil firm Afren fell after announcing that despite 2011 average production increasing year-on-year, it was held back by a longer-than-anticipated period of facilities related downtime at the Ebok field in Nigeria due to safety requirements and commissioning work.Groceries deliverer Ocado was also heading south after the group's Chief Financial Officer, Andrew Bracey, announced his intention to turn over a new leaf at Michael Page, the recruitment firm. Ocado fell while Michael Page nudged higher. FTSE 250 - RisersCable & Wireless Worldwide (CW.) 21.25p +18.72%Renishaw (RSW) 1,198.00p +9.71%Dixons Retail (DXNS) 14.74p +8.94%Carpetright (CPR) 589.00p +5.08%Heritage Oil (HOIL) 195.30p +4.33%Hunting (HTG) 856.00p +4.07%Domino's Pizza UK & IRL (DOM) 476.20p +3.52%Computacenter (CCC) 392.40p +3.45%Soco International (SIA) 304.60p +3.32%Dunelm Group (DNLM) 472.10p +3.12%FTSE 250 - FallersAfren (AFR) 119.10p -4.41%Kesa Electricals (KESA) 69.30p -3.08%Big Yellow Group (BYG) 270.50p -2.28%Drax Group (DRX) 520.50p -2.16%Salamander Energy (SMDR) 243.50p -1.93%Ocado Group (OCDO) 86.00p -1.88%Provident Financial (PFG) 980.50p -1.85%Micro Focus International (MCRO) 447.60p -1.63%DS Smith (SMDS) 230.00p -1.58%Bumi (BUMI) 867.50p -1.53%NR