Provided that i have atpl theory, all requirements, do everything in the same country, even withouth having a validated JAA PPL, i think i could take the skills test.
I wouldnt be able to issue it because i dont have jaa licence to attach it, but the fact of taking the skill test, pass, and not submit it to CAA i think it would be plausible.
I was reading and there is people with JAA PPL, that did JAA IR first than JAA CPL, but didnt issue it, they waited to finish the CPL, so they would issue all in one time (less caa fees to pay)
But has you said when you pass a skill test you are PIC, that maybe a problem if i dont have a JAA licence, how could i log that hour as PIC.