I.d. For Cancellation

Not sure if this question is in the correct category, but I'm sure I'll be told.
These cancels are on the back of a folded letter sent from Paris France to Cheltenham England in 1852. Obviously the black mark is a transit mark stamped in Lingne-du-Calais.
But I'm curios about the red cancellation.
There doesn't appear to be a denomination on the front of the letter. There is a script mark which could be a you or W. So I'm thinking this letter may have been unpaid.
Do you folks think this red mark is a French postal carriers mark, OR a British Duty Mark, which would have been applied to an unpaid letter.

The mark reads AU 30 JA 30 1852




Have at 'er experts!

Please post scans of the entire front and back sides. Trying to interpret a cancel out of the fullest context available is liable to errant interpretations.

Absolutely, sorry John. I should have known better.
Here's an image with front and back. Just a letter cover, no contents.



Just a thought, but I'm leaning toward it being an English mark, myself.

Yes, typical style for a British marking. "AU" is just an internal control for the cancel used, I think probably from London. This style of marking used on stampless covers here:
-/webgil/maritime.html
http://www.postihistoria.info/aihea...nticmail.pdf

Thank you hy-brasil. So you think London transit cancel, on the way to Cheltenham?