Geographical location should be and I hope is irrelevant.
For some reason (I have ideas) however the more Northern Referees seem on balance more successful.
Anyone care to postulate why?
I wonder if there is a difference in observers? Are they perhaps a bit more forgiving up north and harsher down south, leading to better marks overall up north? Are the RA's or RDO's better up north and put more time and effort into supporting and developing their referees maybe? I see what Ross Joyce, for example, does in supporting his baby referees (the 14-18 age group) and he is amazing with the support he himself gives along with the excellent mentoring scheme he has implemented, it will really pay dividends over the coming years.
I have heard many times and from different sources that Observers are more generous in their estimations in the north rather than the south. The point about RDOs is something I have no direct knowledge about but it seems to be a good point well made.