My new 5yo cat has been kept indoors for the month I've had her.  She was
fine with it.  My small backyard has 8' fences, so last week I let her out
to enjoy some sun and have a bit more room to run around in. She loves it
out there.

The trouble is, she vastly prefers to do her business outside and now won't
use the litter tray at all.  In a week she has dug up half the yard and now
it smells outside and it attracts flies.  I absolutely have to change her
back to using the litter tray.

Is there any way I can train her to use the litter tray and still let her
outside?  Unfortunately, if there isn't, I will have to restrict her to
indoors, which would be a shame.  She got very very upset today when I
wouldn't let her out and carried her away from the door.

Nick