JET have replied our question about HVSF PSE certification.
JET don't accept the cross section of the conductor less than 0.50SQMM and the thickness of the HVSF less than 0.80MM.
So for Johoku project, we cannot mark PSE on the cable.
I'll ask RD to design new marking for HVSF 0.14, 0.30SQMM.
Please check the mail from JET as below.