My idiot cat and her toilet habits

[Cyder]

I've got a cat, a very special sort of cat, the kind of cat who is quite happy going outside or in a litter tray to do a wee, but refuses to do a poo outside or in her litter tray instead preferring the floor.

She's an idiot.

Now, I quite like my cat, she has a wonderful temperament and has not a bone of malice in her body aside from her aversion to stting in the right place.

I've got two litter trays, in separate rooms which are nice and clean. In fact one of them is ~6ft away from where she likes to crap.

I've run out of ideas to be honest, this has been going on for quite a long time and I can't work out how to crack it, so short of putting her in a pie or locking her outside I'm open to any thoughts or advice from the masses.