As you've probably realised, PG recruitment doesn't tend to run as far in advance as undergraduate.
So if you take a look at the UCAS postgraduate course search page (https://digital.ucas.com/search), there are a couple of Jan and May 2021 start dates available on midwifery courses but the majority of universities are still recruiting for their September 2020 intake.
You'll probably find a wider variety of choice after September this year as the next round of intakes will then be for Jan, May, and September 2021.
There's also more info available at https://www.ucas.com/postgraduate/ho...aduate-courses. Individual universities will also be able to provide guidance so if there is a uni you're particularly interested in studying at, maybe drop them an email to ask them when their applications open.
Hope that helps!