When you start working her only do 10min walk to start with and gradually build it up to half hour by the end of the first week. You need to take things much slower than you would do normally because she's been out of work for such a long time. Also, carrying all the extra weight will put a strain on her heart, lungs and legs so don't be in a hurry to get her fit. Gradually push the work up to 1 1/2 hrs walking over 4-6wks then cut the time down to 1hr but start trotting, only really short, slow trots to start with. When she's used to doing a bit of trot work you can start gentle schooling and hillwork. Again build the workload up gradually before you think about cantering.

Remember the lungs and heart will adapt to work quicker than the tendons and ligaments, so don't increase her work just because she's stopped blowing, give her legs a chance to "catch up" for a couple of weeks. Avoid too much trotting on the roads while she's so heavy, the concussion of trotting on hard ground, made worse by her weight, could give her laminitis.

Aim for a slow steady weight loss. Whatever you do don't starve her, that will only cause more problems. One or two slices of hay for a 15.2hh overnight won't be enough, even if its in two nets so takes longer to eat. If she comes in at, say, 7pm she'll still run out way before midnight. You don't want to leave her without food for longer than 3hrs or it's bad for her gut health. Have the hay analysed so you can be sure you're not using hay with a high sugar content. If necessary soak the hay for 24hrs to remove most of the nutrients, although it comes out of the bucket smelling vile. I'd try to get hold of poor nutritional quality (not dusty or mouldy) hay first, so you don't have to soak it for so long. Definitely make sure she's gettin enough minerals/vitamins the body doesn't function as well without them. Try a supplement in a handfull of low calorie chaff or a feed balancer. If you use a balancer make sure it's not one designed to put on weight. x