BRMotorsport

I was lucky enough to pick up a BRMotorsport MK2 VW Golf GTI 16V a year or so ago.  Unused since 1999.  It came with no paperwork despite the fact it was owned by the last guy from 1996 ! (Long story).  Anyway, I found the fully stamped service book in the car but I've got nothing else.  The cylinder head is stamped 'BRMotorsport 9609JK'.  Does anybody definitely know what the markings mean please ?  I thought the 9609 could be the date the cylinder head was modified ?  Could the JK be the engineers initials ?  Thank you in advance everyone !

Sorry I know its not a mk1 but this groups seems to very knowledgeable on mk2's as well.  I do have a couple of mk1's as well.