I so can't wait to find out what this secret is!
Basically, Steve and Ben 'hit the nail on the head' when they guessed it. He's told Andrew, and also told Ife just before she was evicted. He says it's nothing to do with his family, or anything to do with Big Brother.. which suggests it's something like just about himself. Steve said 'it's worth knowing' and I think it was Andrew who said 'I can see why he doesn't want anyone to know'. Also in the earlier days Shabby and Caoimhe were guessing and Shabby said he could have a twin or something
Think it's a possible that it could be he's had a sex change, which Dave has previously guessed and Mario laughed it off...