Question: What are the guidelines for coming into the UK?

Answer passage (source: UK):
page_title: Guidance Waiting to return to the UK during coronavirus (COVID-19)
section_headers: Checklist if you are waiting to return to the UK
section_content: If you cannot currently return to the UK:

follow the advice of local authorities, including local measures to help minimise your risk of exposure to coronavirus
find accommodation that is suitable for your needs
check your visa, if you have one for the country you’re in. If it is due to expire, visit our travel advice and read the ‘staying during coronavirus’ section. The Foreign & Commonwealth Office has negotiated with local authorities in some countries to automatically extend visas if you cannot return
contact your travel insurance provider to check your health cover. Most providers will look to extend single trip cover for up to 60 days if you are making every effort to return home
read our travel advice of the country you’re in, in particular the ‘staying during coronavirus’ and ‘return to UK’ sections
sign up to email alerts for the country where you are, so you are notified of any updates

If you need urgent consular help, contact your nearest British embassy, high
commission or consulate.

Reviewer feedback on this answer:
Has information for people stranded outside the UK. Doesn't address what to do if you can travel to the UK.
This answer is irrelevant to the question. This answer is a guidance on what to do if a British citizen cannot currently return to the UK. It does not provide any guidelines for coming into the UK.

Reviewer ratings:
Bad
Bad

Answer passage (source: UK):
page_title: Guidance Travel advice: coronavirus (COVID-19)
section_headers: When you return to the UK: protect yourself and others
section_content: The rules for entering or returning to the UK are changing on 8 June.
Until 7 June
When you return to the UK from a flight from another country, go straight
home, avoiding public transport where possible. If you can, wear a face
covering if you need to use public transport, and see safer travel guidance
for passengers. Only people living in your
household should collect you on arrival.
If you are remaining in England:

stay safe and alert and only go outside for food, health reasons, exercise and recreation, or work if you cannot work from home
when you go out: always stay 2 metres (6 feet) away from other people, do not touch your face, and wash your hands frequently, including as soon as you get home

If you are travelling on to Wales, Scotland or Northern Ireland, follow the
relevant devolved administration guidance:

Welsh Government guidance and see transport advice
Scottish Government guidance and Traveline Scotland advice
Northern Ireland Executive guidance and Translink advice

If you start to have symptoms
For most people, coronavirus (COVID-19) will be a mild illness. However if you
start to have any of these symptoms:

continuous cough
high temperature
loss of or change in your sense of taste or smell

you must go straight home, self-isolate for 7 days and arrange to have a
test to see if you have coronavirus.
See the guidance for households with a possible
infection and call NHS 111 if your symptoms worsen. For further guidance,
visit gov.uk/coronavirus or visit
nhs.uk for specialist medical advice.
From 8 June
From 8 June, there will be new rules for entering or returning to the UK. You
will:

need to provide your journey and contact details when you travel to the UK
not be allowed to leave the place you’re staying for the first 14 days you’re in the UK except in very limited situations (known as ‘self-isolating’)

If you are planning to arrive back in the UK on or after 8 June, you must read
the guidance on entering the UK from 8 June.

Reviewer feedback on this answer:
Has detailed information about the rules for traveling into the UK during different time periods.
This is a direct answer to the question. This answer contains comprehensive information, explanation and guidance on what travelers need to know for entering or returning to the UK.

Reviewer ratings:
Excellent
Excellent

Answer passage (source: UK):
page_title: Entering the UK
section_headers: Who does not need to provide their details or self-isolate for 14 days
section_content: You will not need to fill in the form or self-isolate for 14 days if you’re
travelling to the UK from:

Ireland
the Channel Islands
the Isle of Man

There are other reasons why you might not need to fill in the form or self-
isolate. Read the list of who does not need to fill in the form or self-
isolate.
The rules about who does not need to fill in the form or self-isolate will
remain under review and may change in the future. You’ll be able to find more
information on this page when it’s available.

Reviewer feedback on this answer:
Specifies who doesn't have to self-isolate, which implies everyone else does.
This does not answer the question. The answer does not provide any information on guidelines for coming into the UK. This is an information regarding  people who need and do not need to fill in the form or self-isolate when travelling to the UK.

Reviewer ratings:
Acceptable
Bad