
Ruth,
Prior to me giving up work to care for Katie back in 2007 I used to work as a sponsored childminder with my local social services offering respite care for parents who needed a break..
Kids came to me for all sorts of reasons. One offs for a few hours whereby a foster mother needed to attend a hospital appointment and couldn't take the child with them or parents who needed to go shopping, spend time with their other children or just have a day to themselves to recharge their battries..
I looked after children with all sorts of ailments, ADHD, Autism, Cerebral Palsy, Downs to name a few. Training was on the spot and individual to each child. The only qualification I have is (apart from my initial childminding qualifications) is an NVQ in Autism awareness and intervention and first aid... I never once had to call in the emergency services but once had to call a parent to come and collect their child as he trashed the toyroom including smashing the TV screen with his head.. (Turned out his parents forgot to give him his ADHD medication that morning)
The kids did not see it a care, they just came to play at Auntie Shellys.. Care was always one on one and I know the kids benefited from the seperation too, quite often they didn't want to go home

So such care is available, contact your local social services and enquire if they have any sponsored childminders in your area.. Childminders have to have sooo many qualifications now a days as they are regulated by Ofsted you are sure to find one in your area where Em could go and 'play' and you would be confident in leaving her there. No preperation required after the initial visit, you just drop and go.. lol
You should be able to claim direct payments too to pay for the childminders services check out
http://www.direct.gov.uk/en/DisabledPeople/FinancialSupport/DG_10016128 as once parents had involved social services in finding respite care for their children they then applied for direct payment s to pay for the care.. The rate 3 years ago was £8.50 an hour for my area, I have no idea how much such childcare would cost now.
Let me know how you get on.

Shelly..xx