I fell into luck: Boomerang UK's still airing it, and my friend in Portugal's able to cap for me.
While not perfect, from Puto's test cap and with a little help from GonbeFAN, I now have a reasonable-quality copy of the OP without the edits.
I'm able to do a mostly passable job getting rid of the station logo, too. Hopefully x264 compression will fudge out the artifacts a bit more.