I won't post in the Childminders nannies etc topic but have read the thread.
I would expect them to terminate your employment, which they can do with no problems this early in your employment. That gives them maximum options, and if your op and recovery goes smoothly, hopefully they will re-employ you.
They won't be obliged to do so and it saves them messing about with SSP and the uncertainty involved as well.
It's obviously disappointing for you but not illegal for them to do.