My Granma always used to 'pin the devil' if she couldn't find something. Nine times out of ten it would work. Stick a pin in the back of your sofa and say "I pin the devil to find .....'s lost shoe" I know it sounds daft but I always think anything is worth a try. Good luck
I have trained both our horses (one a mare and the other a gelding) who are on rubber mats to wee into a bucket. One wees to a whistle and the other to a long drawn out "gooood girl". It works 90% of the time and makes such a difference to the amount of bedding you need to use. Yr mare would...