I have found another UK Immigration document.
Immigration Directorate Instruction
Family Migration:
Part 8: Annex F
Adequate Maintenance &
Accommodation
It appears to be aimed at Immigration Officers.
The gist of the accommodation and maintenance appears to be that the sponsor or applicant must meet the same standards that UK citizens adhere too. This come from a high court judgement that all UK citizens must adhere to UK standards in this case, regarding accommodation and financial matters and that immigration policy should not allow immigrants to "live" in a situation which does not reach the UK standard. Even if the immigrants are willing to.
Accommodation has to be legally owned or rented, it has to have the required number of rooms/bedrooms. If living with family members then evidence from them indication the above, and permission to be accommodated, is required.
Maintenance follows the same guidelines. Citizens of the UK are able to claim benefits if they have a small income. These are many and will apply to some or not.
The official definition of being able to show one has enough income or cash
to pass the test of exceeding what a standard UK citizen could
claim, and be awarded, in benefits. Not as I originally believed a fixed amount.
Here is the link to the very straightforward and "possibly" pertinent document.
https://www.gov.uk/government/upload..._8_Annex_F.pdf