The UKVI website includes Entry Clearance Guidance which is used in making entry clearance decisions. https://www.gov.uk/topic/immigration-operational-guidance/entry-clearance-guidance
Click on this to see guidance about issues such as maintenance and accommodation, medical examinations, and all criteria in the rules.
The Windrush scheme was set up to help people who come within the remit of the scheme to prove their settled status.
Guidance for the Windrush scheme is here: Windrush scheme casework guidance - GOV.UK (www.gov.uk).
The Windrush Scheme applies to Commonwealth citizens who:
- were settled in the UK before 1 January 1973 and have lived continuously in the UK since their arrival
- were settled in the UK before 1 January 1973 whose settled status has lapsed because they left the UK for a period of more than two years
- have the right of abode in the UK.
- a child of a Commonwealth citizen who was settled in the UK before 1 January 1973, where the child was born in the UK or arrived in the UK before the age of 18, and has lived continuously in the UK since their arrival
- a person of any nationality, who arrived in the UK before 31 December 1988
See also the links provided for chapter 3.