Bizzarely, you download the file at the above URL (1.5MB) but then have to rename it by adding .pdf at the end... then you can view it as normal.
Page 43 deals with audiology for the instrument rating (and for the proposed EIR).
fitness of class 2 applicants for an instrument rating or en route instrument rating with the condition specified in (b)(1) shall be assessed in consultation with the licensing authority.
(b)(1) is a loss of hearing
On my reading, this means the individual CAAs are able to allow a pilot deaf in one ear to get the IR (or the EIR, if it arrives). Previously the JARs did not allow this, and one had to use some other routes.
More on page 93.