require group is ignored when AuthzSVNCrowdAccessFile is used

This works as expected:

<Location /repos>
DAV svn
SVN Path /srv/svn/repos

AuthName "Crowd"
AuthType Basic
AuthBasicProvider crowd
CrowdAppName subversion
CrowdAppPassword ...
CrowdURL http://crowd1.prod.example.com:8080/crowd/

1. default timeout=0 (infinite)
   CrowdTimeout 30
2. default maxage=120secs
   #CrowdCacheMaxAge 5
3. Improves performance when using Subversion clients that don't store cookies
   CrowdCreateSSO off
4. Crowd is authoritative, not authz
   AuthzSVNCrowdAuthoritative on
   AuthzUserAuthoritative Off

Require group Enterprise

1. AuthzSVNCrowdAccessFile /etc/subversion/crowdauthz.repos
   </Location>

However if I uncomment the AuthzSVNCrowdAccessFile line, all valid-users can login. I've tried setting AuthzSVNCrowdAuthoritative to off but that makes no difference.

I know that as of apache 2.2 using a require group for LDAP is sadly limited like this as well as per:
http://www.svnforum.org/threads/37237-AuthzSVNAccessFile-Require-ldap-group

It's not clear from the crowd docs if you can only use valid-user (the require group is used in the apache config so you'd assume that it would work).

TBH this might be a case of "sorry, apache issue, not crowd, but we'll document it". It's a nuisance as otherwise the two options are:
a) rely on AuthzSVNCrowdAccessFile to reject everyone you don't want
b) define a new crowd app for every subversion repo (assuming they have different group requirements)