So I moved my WordPress install to my domain root and the WordPress specific htaccess instructions have borked my WebDAV. Fortunately a little googling and I’ve got a solution.
Since running a multisite install, my htaccess rewrites a lot. Turning off the RewriteEngine inside he WebDAV direcetory solves this issue.
<IfModule mod_rewrite.c> RewriteEngine Off </IfModule>