Sorry, I didn't make myself clear. The film is between the two panes. If it
were not I could simply wipe it off (i.e. clean the windows!).

I was told that the space between the panes was originally evacuated, and
when the vacuum fails (after 8 - 10 years) the filming occurs and the unit
needs to be replaced. If this is true I would be tempted to get rid of the
double glazing and go back to normal windows that at least could be cleaned
properly.


I don't think that gap was ever a vacuum.
I've never had this happen on dg units, even on one that I accidentally
cracked. That used to steam up very slightly in the corner where the
crack was, but never got any worse.