Yup, I have access to CAP493 MATS pt1, 493 and all the other CAPs on the CAA website.
What I'm trying to say however, is that his instruction didn't make sense. This is the thing, "no altitude restriction" is not clear. He cannot give us a level restriction OCAS in Class G open FIR, as we were under VFR. So one could assume he was saying, you can enter CAS at your discretion, but not above the TA. Yet this would be unofficial - as it's not any type of solid clearance. Also, he didn't say "Remain clear of CAS" as they normally do, this would work in favour of a unofficial clearance. We weren't under a SVFR or IFR clearance. We're being given a FIS (which, I correctly accept as a service also in CAS, but in the case of Cardiff - really only given OCAS).