The human performance and limitation certificate only applies to some countries. The UK doesn't have one so when I applied I put N/A in there.
Are you sure of that ?
What about the certificate HPL (040), of course UK has one but you are not concern because you have a frozen or full ATPL, we are talking about JAA licence here, for the non JAA there will have to undergo a 5 days course except if they can provide a certificate.
So to make it simple if you hold a JAA frozen or full ATPL you are not concerned because it's certificate you get during your ATPL exams, for other people holding a CAR/FAA/etc.... you have to furnish a certificate or you will have to undergo the 5 days course during your ground training, simple as that.