40D suddenly producing large RAW files

A bit of a strange one, my 40D for no apparent reason has started producing larger RAW files, by larger I mean in order of almost three times what it used to (from 8-12MB to 20-30MB).
No settings I am aware of have been changed and the issue does not seem to be related to ISO (files still larger at ISO100).
The camera has always been set to take full res RAWs so it is not me suddenly changing to full res either.
The images process fine and look OK.

Thoughts?

Typical, after a couple of hours researching and scratching my head, minutes after I post this I figured it out.
It is the Digital Lens Optimiser in DPP, it significantly increases the size of the RAW file.

There you go, I will no return you to your scheduled programming.