Standard -6 month visit visa for my mum.

Hello,

I recently applied for my mother's standard 6-month visit visa for the UK. I have yet to attach her evidence documents and upload a cover letter since her biometrics are scheduled for Monday. I wanted to re-check the list of documents to ensure there is no room for error from our end and she has a greater chance of visa approval.

Background of her application:

1. She is a housewife, completely dependent on her husband’s (my father’s) income. She only has one child (me). I am financially dependent, but I still live with my parents. My father also has a residency permit from another country (non-UK and EU).
2. We live in a rental home. However, she has a bank account in her name where she receives regular remittances from my dad. She is also a registered tax filer.
3. She was invited to the UK by her eldest paternal uncle. He is a retired NHS surgeon and has been a taxpayer in the UK since the 1970s. He holds a respectable social status there and is now too old to travel. He last met my mother 2-3 decades ago. My mother’s parents are no longer alive, and her uncle wants her to visit him for a while now. He sent his stamped letter of invitation and a letter from his registered tax lawyer in the UK to assure that he is of sound financial standing and in no violation of UK laws and immigration.
4. My uncle is sponsoring my mom’s UK visit. However, she has sufficient funds in her bank account and can easily pay for her visit.
5. She will travel alone and only spend 25 days there with her uncle and his family. My dad and I will be staying behind.
6. She hasn’t traveled anywhere since 2001. However, she visited the UK in childhood, had a residency permit in another first-world country, and has been to Singapore. She has never been refused a visa in her travels. She wasn’t able to travel after my birth due to her own health complications.

Now, here are the documents we are attaching, and I need to know if these are good to go or if I am required to attach anything else;

Documents:
1. Her bank statements for the last six months
2. Her uncle's invitation letter
3. Her uncle's lawyer's letter
4. My dad's letter for sponsoring her
5. I am told to attach a cover letter (But I am unsure where I will be attaching it in the first place, so any help here is welcome).
6. She has her income tax returns (Should I attach these somewhere, or will they only be considered extras?)
7. She is attaching her family documents to show evidence of her relationship with her uncle

Are these concrete enough? Most cases from my country get rejected since they are suspected of slipping away in the UK. What else can I reasonably include to ensure no loopholes in her application? Thank you.

Socio-economic ties; evidence of strong ties to home country that will spur her returning after proposed period of visit, evidence of financial situation and explanations of the income or inflow into her account.
That you and dad are not going can be a plus to the application.
Do add the tax details you mentioned above.
Cover letter in like manner as you did in your post above.
The supporting documents or evidence can be uploaded under any of the sections, the ECO will go through them all. What is important is to upload ALL such relevant documents.

This is helpful, thank you so much for your prompt response!