By Sam Elliott-Gibbs Celebrity Big Brother viewers teased that Louis Walsh has really been doing his homework after noticing he ‘knows everyone’. They demanded to know what’s going on as the very clued up Irish star started reeling off the names of most of the arrivals – even briefing oblivious Sharon Osbourne about their new housemates from their secret location. The former X Factor judge, 71, entered the house to join pal Sharon and soon they were ushered into another room to judge their fellow contestants. In-the-know Louis explained in detail who each new celeb was, leaving viewers compari…