I’d like to think that at least people with no means to buy a home shelter were provided with one by their local authority, if there was no nearby subterranean shelter for them to use…
I'm currently reading '
The Battle of London, 1939 - 45', by Jerry White which mentions shelters, although not sure it's mentioned specific advice what to do. i think by a certain point, there were shelters close to everywhere, with communal shelters in areas where people wouldn't have shelters in the garden. air raid precautions was set up in 1937, but started getting taken more seriously after munich 1938.
'running past' blog (fairly localised on the lewisham patch) has a piece about ARP
here.
This confirms that
Anderson shelters were issued free to households with a weekly income of less than £ 7 a week
Although shelters you could dig / build in your garden weren't a lot of use if you didn't have a garden, past tense has more on this, including the stepney communist party organising
an outing to the savoy hotel's shelter in 1940.
The later indoor
Morrison shelter was also free to lower income families.
To put the income in to perspective, a London tram driver was on a bit more than £ 4 a week at the start of the 1939 war and that was a fairly good working class wage at the time (bus men got slightly more than that but I don't have a figure to hand.)
This (on an isle of dogs history site) has more about cellars, church crypts, railway arches and trench shelters as public shelters, and also a picture of a brick / concrete communal street shelter.
and some blocks of (private) flats built in 1938 / 39 had an air raid shelter as part of the design - there's
a surviving one in east sheen