Another name to throw into the mix is Tom New, Nixon's understudy at Leicestershire. How much exposure he gets will depend on whether or not Nixon gets a test call up or not, however he's only 22, so has plenty of time.
By the way, does anyone have any thoughts on when a keepers 'peak' years are considered to fall between? I'd have thought it would have been around 29 - 33 but can't ever remember it being discussed.