git-svn trouble finding all branches/tags

Scenario is initialization of a local git repo from a remote SVN repo.

$ git svn init -s https://svn.our.office/projname

$ git svn fetch .........................

Now, git branch -r shows trunk, one branch, 3 tags. There ought to be 7 branches, and about 20 tags.

If I go into .git/svn/.metadata and change the 

branches-maxRev tags-maxRev

values to something much larger than anything in SVN (e.g. 1000000), and repeat 'git svn fetch', lather, rinse repeat, then I eventually have all the branches and tags.

Surely this isn't the way its supposed to happen?

TIA.

Michael