Kern - almost right but no cigar.
The guy you mention is Gavin Webber and the cheese he added peppercorns to was farmhouse cheddar, not Caerphilly. The recipe is in his book which is available as an electronic download 'Keep Calm and Make Cheese' from his website
www.greeningofgavin.com He recommends using either green or pink peppercorns but not black. I have actually made this recipe using red peppercorns and can recommend it. The method is as Kern states.
In his book he actually takes it one stage further and added some PR to the mix to make what he calls 'farmhouse pepper blue'. I have not tried this but the author rates it very highly.