Likewise, should display pilots be required to hold or have held a professional pilots qualification (ATPL/RAF wings)
Couldn't that mean someone had spent some time flying transport aircraft, which wouldn't be any qualification to display a historic jet fighter?
Agreed, Phil.
As well as qualifications on paper, there is the issue of currency. How is currency maintained in the civilian world flying similar, ex-military aircraft?*
*I am in no way doubting the experience, the currency or the credentials of the pilot in question.