In answer to your first question- I hav'nt got a horse on livery there but know the yard quite well.
I think it suits some horses more than others. You can't fault the standard of care at MW- both the yard manager and head girl are great horse people. The horses are all healthy and happy and well looked after.
If I had a horse that I was looking to put on Working Livery I would definately consider MW as an option
Mine was there about 3yrs ago. Postives and Negatives, she was there a year and on balance I wouldn't ever put a horse on working livery again ANYWHERE by choice. I think a few thing have changed as they were struggling at the time to attract working liveries.
They had very limited grazing (as farm manager seemed more intersted in keeping the grass looking nice, than giving the horses access to grazing), especially in winter, horses don't (or didn't whilst I was there) go out at all during the week, then got put out either all day & night Sat, or all day & night Sun. Sometimes they don't get to go out at all over the weekend and sometimes they were put out Friday afternoon and not brought in till Sunday, to then be in 24/7 through the week. They were also put out 24/7 during all college holidays (was given the option of going DIY over Christmas, so my mare stayed in rather than out 24/7 on snow covered fields).
Care varied depending on which student was responsible for your horse and who had used it last. Sometimes found mine with no hay at 6pm, once arrived early to find her hot and sweating after coming out of a jumping lesson, fully rugged for the night and eating her dinner. Found my bit on upside down more than once!!! My mare was kicked whilst in a lesson (another horse was allowed to run backwards into her and boot her, yet I still had to pay the vets bill!!), she was off work for nearly 6 weeks. My mare also had a nosebled that I wasn't told about, until she had one when I was ridding 2 days later and someone then mention she had had one before.
Whilst the facilities look great in reality we didn't get much use of them. Most evening the indoor school was being used for shows, or evening classes or was being or had been prepared for a show the next day (this may have changed).
Not sure what happens during the summer holidays now, as there wasn't DIY at the top yard then, but when I was there horses were basically on grass livery for the summer (don't think there was a reduction in livery charge) , and pony clubs rented the main yards and schools, so we could only use the top yard then, but horses were often a long walk from it, so ended up tacking-up in carpark.
Some of the fields didn't have mains fed water troughs, and these ran dry on several occasions, as relied on estate person being contacted to top them up from a bowser on a tractor.
Don't think the actual work caused my mare any issues and her jumping improved (mainly because she did more jumping there as I had done very little jumping with her previously).