I've just returned from HR and played golf with my father. I did have my certificate but my father didn't. They asked for it but still let him play without it.
A simple trick I've used in the past for golfers who aren't club members is to produce my own handicap certificate in the same format as a club certificate.
This is particularly useful for society golfers and it's worked across Spain and Portugal.
I would say however that the HR golf course is quite difficult (I'm off 7) and the handicap restrictions should apply regardless of how you obtain a certificate.
If you can't shoot around 100 then avoid playing until you have improved.