Entry Clearance (visitor visa) UK confusion

[rbsjp]

My mother is in UK on visitor visa
Her Indian passport has a vignette which says ENTRY CLEARENCE MULT C-VISIT valid from 27/08/2020 to 27/02/2021 Duration 180 days. She came to UK on 27 Sept 2020. How long can she stay in UK legally for . Is it 180 days from day of landing in UK or till the validity of Entry clearance, which will be sooner?
Thank you for answering.

[CR001]

She must leave the UK by the date her visa expires.

The 180 days is the visa validity on the visa vignette.

When she entered the UK is irrelevant to that.

[rbsjp]

Is it possible to delay, with the lockdown and pandemic going on. I dont want her to travel as it wont be safe.

[CR001]

If she doesn't leave the UK by the time her visa expires, she will be an overstayer and risk refusal for any future apllicairkns.

As she travelled to the UK during a pandemic and taking the risk, there is no reason she cannot leave. Your pandemic argument would be incredibly weak.

[rbsjp]

Thank you.
Just a hypothetical question: If she is not able to leave by the date of expiry of her visa, I understand she may never get a UK visa to come back. Will it affect her application to other countries as my sister lives in Australia and brother in Canada. Will it affect me because I sponsored her visitor visa. I am a British Citizen but my family will be applying for ILR shortly

[vinny]

If you’re in the UK

If you intend to leave the UK but have not been able to do so and you have a visa or leave that expires between 1 January 2021 and 28 February 2021 you may request additional time to stay, known as ‘exceptional assurance’.