I take it there aren't many images available for this series? One thing you could do would be to replace the bottom image on each one, if there are limited images. A google search reveals a few small ones, but enough to change a small portion. Images such as
would be a good substitution. The easiest way to do this would be to erase the bottom image, using a large soft brush, making sure you have a clear layer below. (see image 1) I also duplicated the image, so I could ensure the blade stayed sharp. The top layer consists of pretty much only the blade.
After this, I simply copied in the other image below. I had to clone some sky in order to make it fit properly. (image 2) You'd then add your font.
It's a very quick way of ensuring some variation, and as the image only needs to be (high quality) about 400x300 it's easy enough to find some.
I like the celtic font, as well as the placement and transparency.
As for the colour grading, it would work better if the whole image was graded - having the logo ungraded makes it look a little strange. I suppose you are aiming for an old photograph sort of look, right?
So have a go substituting images, and see what happens. If you wanted to substitute the top one, you could also do a search for the BBC logo, and then add that on top to keep it all looking the same.
Sorry if this all sounded a little patronising! Good luck with the images, post them up when you've had a pop!