Have used small-mid sized hatchback cars with stick shifts here in the UK for around 30 years and haven't had many problems with accessing places, even in the days when I was working as an outdoor instructor and driving a Mark 1 VW Golf.
All of the cars have been used to access basic or not-so-basic campsites in the UK.
Whilst 4x4 vehicles may get you almost anywhere in the UK, unless you're dealing with snow and ice, there's no real need to have one in my opinion. Trying to negotiate some roads in the Yorkshire Dales or the Lake District was a pain last year - the roads were wide enough for two regular size cars to pass when going in opposite directions.
Put a 4x4 or a large car in one lane and it becomes and interesting situation or a bigger pain on roads such as the one connecting Langdale with Little Langdale that starts off near The Old Dungeon Ghyll pub...
Turned out that I knew the driver of the Beemer that caused one of the biggest problems because I used to work for him! Pure coincidence I hasten to add...