Welcome to the forum

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Now I thought we had the process sorted out, but on reading the forums I'm beginning to doubt myself, as I understand it he has to return to America to start the formal process of coming here as a fiancée, I work full time earning enough (with contractual out of hours bonus) to meet the £18600 financial req.
There are a couple of options.
He could do the fiance visa to marry in the UK, but he wouldn't be allowed to work or use the NHS until after you are married and have applied for the FLR(M) visa for him to stay.
Or you could fly to the US too, get married there, and then apply for a spousal visa for him, which would allow him to work and use the NHS immediately.
He needs to apply for a visa using the VAF4A family settlement visa form online under appendix 2?
He fills out two forms:
- online application (this should be the last thing he does when he's completely ready to apply)
- VAF4a Appendix 2
We also have to fill out the financial requirement form.. because I will be his sponsor do I do this or does he fill this out online also? If he fills this out do I need to do the sponsorship undertaking also?
He prints and fills out VAF4a Appendix 2 himself. However, it will ask for your details, so he will need those.
The Sponsorship Undertaking form is not required for a fiance or spousal visa, so you DO NOT fill it out.
I read on one of the posts that I may need to include my child's birth certificate, presumably to prove that she is also a British citizen and not counted in the additional financial req.?
No, you do not need to include any childrens' birth certificates for this visa.
It will be required for the next visa though, FLR(M).
I can provide payslips and bank statements, pics and logs on chat/phone calls etc but cannot prove intent to marry as we cannot give notice without the correct visa and the place we would like to get married only offers a 2 week reservation and clearly we will not have the visa in that time frame and difficult to book somewhere if we don't know when the visa will be granted etc, how do we prove that without those things?
All you need for intend to marry is an email chain from the registry office/church enquiring about possible ceremony dates.
You can also include things like pictures of the rings/dress etc.
My house is a council rented house, I can show the original tenancy agreement which shows how many people can live within the property, will this be enough or do I also need to include a letter from the landlord? Do I even need to provide that as its a 2 bedroom property with one child's room and our shared bedroom?
You must provide a letter from the landlord explicitly giving permission for him to live in the property with you... you have to prove that he, personally, has permission to live in a UK property.