Posted: 02/04/2013 at 21:49
This site has a list of suitable pollinators for Braeburn http://www.orangepippintrees.co.uk/pollinationchecker.aspx?v=1008 . Braeburn self fertile and will fruit without cross-pollination but yield will be heavier with a suitable tree nearby.
Conference is also self-fertile - the same website describes it as 'genuinely self fertile' and says that it does not need cross-pollination, and that has been my experience.
As for distance apart, without knowing which rootstock they're grafted onto we can't tell how large they will grow. Have a look here http://www.orangepippintrees.co.uk/articles/fruit-tree-spacing-guide - I think I'd assume they're on dwarf or semi-dwarf rootstocks.