The anomoly of there being some aircraft on a Permit and others of the same type having to be on a CoA stems from a change of heart in the mid/late 1990's by the CAA. Up to that point many Cubs, Jodels, Luscombes etc were imported and allowed to go straight onto a Permit, then the gravy train hit the buffers and new arrivals had to go on a CoA, pretty much ending the import of these types because it was no longer considered viable. A great shame really as I don't doubt that many more interesting old Classic and Vintage types would have graced our shores had they still been allowed to go onto a Permit.