Welcome to the forum

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1: I know the fee is £1500 something for the visa and £500 for the NHS charge. I might see if I can get the fee waived as I am on the benefit. I know this only lasts for 6 months and then we need to apply to extend at the end of the period, but is there any charge to extend this to the right to remain for 2.5 or is it covered under the first application??
If you will be marrying in the UK, she needs to apply for a fiance visa, not a spousal visa. This means an extra visa to apply for compared to marrying in the US, plus it can be time-consuming and a hassle to get married in the UK. It will be anywhere from 35 to 77 days from her arriving in the UK to her being able to get married (7 days residency before giving notice, then anywhere from 28 to 70 days to be allowed to marry after that).
Alternatively, if you can fly over to the US, you can marry in 24-48 hours without a visa, and apply for a spousal visa instead of a fiance visa, which will save you about £1,000 in visa fees.
Also, the IHS surcharge doubled in January 2019, so it is now £400 per year of the visa.
The current fees for the fiance visa are:
Visa fee = £1523
Priority service, if using = £573
Shipping labels = up to $140
There is no IHS to pay, but she will not qualify for free NHS treatment, so will need health insurance and will have to pay full price for any NHS treatment during the 6 months of the fiance visa.
Alternatively, if you marry in the US, the spousal visa fees are:
Visa fee = £1523
IHS surcharge = £1200 (£400 per year of the visa, but as the visa is 2 years 9 months, you have to pay for 3 years)
Priority service, if you wish to use it = £573 (it will get the visa processed in about half the normal time)
Shipping labels = up to $140
After you are married, if she gets a fiance visa, you will need to apply for FLR(M) for 2.5 years. The current fees are (but they are likely to rise each year):
FLR(M) visa fee = £1033
IHS surcharge for 2.5 years = £1,000 (£400 per year for 2.5 years)
Premium service, if you wish to use it = £800
Then after those 2.5 years, she has to apply for another FLR(M) visa:
VIsa fee = £1033
IHS surcharge = £1000
Priority service, if using = £800
After 5 years in the UK on the fiance visa and 2 FLR(M) visas, (or a spousal visa and 1 FLR(M)) she will apply for ILR (permanent residence). ILR currently costs £2,389 but it may well rise.
Once she has ILR she can apply for citizenship. This currently costs £1,330.
So, if you marry in the US, you apply for:
- Spousal visa (£1523 plus £1200 IHS)
- FLR(M) (£1033 plus £1000 IHS)
- ILR (£2389)
- Citizenship (£1330)
Total visa fees (at current prices, not including any priority services) = £8475
But if you marry in the UK, you apply for:
- Fiance visa (£1523, no IHS, but she is not entitled to free NHS care and will need insurance and to pay for all treatment)
- FLR(M) (£1033 plus £1000 IHS)
- FLR(M) (£1033 plus £1000 IHS)
- ILR (£2389)
- CItizenship (£1330)
Total visa fees (at current prices, not including any priority services) = £9308
In all, you want to budget £10,000-12,000 in visa fees over the next 5 years, to account for fee increases and priority services.
2: Will there be any issues with living with my parents and also I am currently unemployed due to my care duties and I am only bringing in the Carer Allowance and the carer component of Universal Credit, so will this be ok to show that I can support her over?
You need to be able to show that, after paying any rent and council tax, you have at least £114.85 left over each week to support her.
3: My fiance has disability issues and I was wondering if this will have any bearing on her application to come over her as she can't work atm due to them.
Nope, no bearing. The responsibility is on you to prove you can support her without her needing to work.
4: Who has to submit the documents for proof? my Fiance has no printer so can't print anything over there, but I can do all this but she has to apply from the US to come over here. Also will an email to the registrar, the purchase of the engagement ring and also the purchase of the wedding rings be classed as proof of our intentions?
She submits the application (you mail your documents to her) and she needs to be able to print the online application and Appendix 2, along with her biometrics appointment sheet, plus any copies of original documents she is sending.
Can she go to a local library to print everything? Or maybe ask a friend?
For proof of intent to marry in the UK, you provide an email chain with the church or registry office enquiring about possible dates (but don't book anything until she has the visa).
If you marry in the US, you instead provide your marriage certificate.