T&G,
I think you ought to look at the immigration differences between the two countries.
If an Antipodean has no ancestral rights to the UK (or Europe) then as a pilot it is practically impossible to emigrate here. As a British pilot it is possible to emigrate to Australia.
To emigrate to the UK you have to have higher degrees such as a masters or PhD and/or be very prominent in the business field.
With respect to the licences, the conversion between a UK licence to an Australian one is comparatively easy.
I never said the UK was a closed shop. Just trying to get the CAA to be consistent is a challenge. This affects the locals as much as it affects the "foreigners".