[Anthony B]

thanks for input guys.....

These cars were incredibly 'oily' from the release agent and hence my scrubbing with a cleaner .

An update:  I completely resanded the Ferrari and then sprayed it with Halfords Red primer - got full coverage.

The issue I believe is with the local primers I have been able to lay my hands on as my Halfords grey primer is finished. And by looks of it I cannot get more  due to lockdown and I cannot get across the channel to get some more 

I assume Halfords is closed in the UK at the moment?