phranque - 7:10 pm on May 13, 2013 (gmt 0)
RedirectMatch is a mod_alias directive which shouldn't be mixed with mod_rewrite directives.
I would suggest using a RewriteRule directive with the [R=301,L] flags and put it before the WP internal rewrite ruleset.
also you probably don't need the IfModule.
you either have the module or WP won't work.
you can also drop the RewriteBase directive.