Confused with childcare/ nursery / preschool system

[Nthomp03]

Hi- I am moving from Australia to London next year and my son will be 22 months when we arrive. He also has additional needs but so far is managing ok in a private mainstream childcare and preschool facility here. I am confused at what each of the terms mean over there - preschool, childcare, nursery, day nursery etc. Here in Australia my son attends a childcare that has an attached preschool facility they can attend from 6 weeks old until they start school aged 5. Preschool is a more structured environment that 4 year olds attend before they start school ( at age 5/ turning 5). The centre bourse are 7.30-6 but preschool hours shorter. I am not familiar with the term nursery or pre-prep.
Could someone please explain the system to me there?i am not planning on working, he would be attending for socialisation etc. should I be searching for a day nursery, or a prep- pre school? We are likely to be in the uk for 3-4 years so he would be 4 or 5 when we leave. Thanks

This is my rough idea -although I might be wrong!

Childcare is the catchall term for people who look after children including nurseries, nannies, childminders, before and afterschool clubs.

Nurseries refer to the place you put a baby/toddler/child -these might be birth-preschool type places or preschools.

Preschools do the year (or two) before a child goes to school -they are often referred to as nurseries and are often attached to a school and sometimes only half days.

A Pre-prep (pre-preparatory) is an early primary (infants) private school before going to a prep (preparatory) school which is a primary school which is to "prepare" a child to go to a proper private school.

I'm afraid Jenny is right - it's very confusing because so many of the terms are interchangeable.
I work in 'Early Years' (which covers 0 - 5 yr olds) and I can go from one setting to another that have the same title but are very different set ups, but then between 2 that are very similar in the way they are set up, but they've called themselves different names (Pre-school/playgroup/Nursery/Day Nursery / Childrens Centre / etc.)