Pork souvlaki with oregano

This is from Rick Stein's 'From Venice to Istanbul' which I got as a present a couple of years ago and have still not made much from.  The weather has been so glorious lately that I've been trying to up my skills in barbecuing and thought this would be ideal.  Rick suggests pork shoulder but I had a nice big piece of fillet in the freezer so I went for it.  It was the first thing I put on the barbie and it was perfect.  We had it in pita bread with a feta salad on the side.   Would make again.