The CPL and IR at the same school, the only place I ever saw that as a requirement was on the Flybe application form (not that relevant now). Since that appeared on the Flybe application form everyone started to falsely spread this around as a requirement that everyone had. There could well be a few other airlines that have that requirement, but I am not aware of that many.
A few years back when flybe was a big employer of low houred pilots it probably made it worth doing CPL and IR at the same place.