The 1980 handbook states under the benefits of membership "free parking is granted where the facilities permit it".
As far as I can recall this has always been touted as a benefit of membership (and I have been a member for over 36 years).
The facilities permit it (on a first come first served basis) at Chelmsford, because Premier Suite members will get it for free, so I would suggest Life Members who have joined BEFORE 2015, when this charging decision has been made, should also get it for free.
It does not affect me as I am not a life member, but I would have thought life members should be treated as well, if not better than a Premier Suite member.