OP are you international or from another country? Just when you say you don't know much about English geography.
I agree with pps, I can see you're looking for a change and it must be difficult, but please please take your time.
I think most pps are expressing that you really don't want to rush into the English country/rural fantasy. You may be craving solitude and peace of mind. But buying/committing is very different to seeing.
I love the country, but it's affordable to just Airbnb occasionally to get my fix. I visit a relative in an AONB and the views are idyllic, getting in and out is a nightmare!
Every place has problems, children may feel unsettled. In a big city, it's much, much easy to you all to switch up social groups and find new people and find your niche and your tribe. There's always people coming and going
If your face doesn't fit in a small community it can be hell - it's not like the films or books where a dashing rich local farmer will step in to save the day.
If you're single/just divorced woman outsider coming in it could be especially horrific to find a support network.
Even if you're introverted and feel you'd be happy being quite solitary in the greenery, having people 'bristling" at your presence is traumatic.
There are some big cities where green suburban spaces are cheaper.
So you may get your green/peaceful fix without having to go completely rural. A budget like you have could go far (and spare money for an Airbnb or travelling if you need)
If you want some sort of retreat year, (very understandable given current circumstances), I wouldn't make any drastic decisions?
Spend money on therapy or coaching or building up self-care and support systems rather than changing life so drastically. Find an allotment or community garden to help out at. Rent a country place on Airbnb for 3 months in the winter.
Even if you do make the big move, you don't want to be coming from a vulnerable position.