C41/ E6 processing error - is there a digital fix?

Hi people,
I *think* this group is likely appropriate, but if I'm wrong,
any pointers to a more suitable group?
A few days ago I took a couple of rolls of film into the local
Tescos (UK) to get them processed. I told the operator that one was a
slide film and one a print film, but I didn't remember the reason I
mentioned this - we then got into a confused discussion because I only
wanted a set of index prints - when I still had chemical cameras I only
used slide, but my fiancee uses print - like I said, confusion.
Anyway, the operator put both films through the same process. I
can't remember which one it was, E6 or C41, but the slide film (a
36exp) came back with a screwed-up green cast and the print film was
OK.
We didn't have time to argue the toss with the operator - next
day we were on a train for 500 miles - so I grabbed the mis-processed
film and ran. (at least they didn't charge us for the processing. Small
mercies G).
I'm planning to put the mis-processed film into the local
Jessops to get it scanned to CD because I *hope* that a series of
digital manipulations (separate out into 3 colour layers, then
re-composite those applying different colours to those layers and
re-compositing) will allow me to at least get a reasonable
approximation of the correct images out.
Anyone know how to do this in detail. Digital tools available
are Gimp 2, but I have friends with Photoshop if I have to. I'm green
at digital processing, but I've a working understanding of what's
actually going on, having done enough darkroom time in the dim and
distant past.

--
Aidan Karley,
Aberdeen, Scotland,
Location: 57°10'11" N, 02°08'43" W (sub-tropical Aberdeen), 0.021233

Aidan,
This is "cross processing", and for many people this is a preferred effect. Can you fix it digitally, maybe, it depends on the desity of the greens and reds, usually it apears almost painterly, thus creating difficulty in getting a clear image. You should be able to fix the color for the most part digitally, however the image may not ever be as sharp as you have wanted.