Can anyone confirm the earliest and latest date by which an ILR application needs to made?
The earliest date you can apply is 28 days before you reach 5 years in the UK... so the exact date will depend on what date you first entered on your spousal visa.
The latest date you can apply is the expiry of your current BRP card... you only need to have submitted the online application by that date - the rest (biometrics and processing) can be done afterwards.
I see from your previous posts that your wife entered the UK on 8th November 2017 and that her current BRP expires on 22nd April 2023.
She will reach 5 years on 8th November 2022, and can apply for ILR 28 days before that, so her window to apply for ILR will be:
11th October 2022 to 22nd April 2023.
Also, just wanting to check that the correct fees are £2,398 for the application fee?
The ILR fee is £2,389 plus £19.20 for the biometrics fee, so you should be charged £2,408.20.
The biometrics appointment itself may cost up to £130, depending on what appointment type you can get... there are some free appointments, but there aren't often many available so often people end up having to pay for an appointment.
Also, if you want to use Super Priority processing for a decision within 24 hours of biometrics, it costs an extra £800, added at the time of paying the visa fee. If you don't use Super Priority, it can take 6 months for processing.
Additionally, does my wife need to wait a further 12 months after ILR approval to apply for citizenship?
No, if she is married to a UK citizen, she can apply for citizenship immediately after receiving ILR, as long as she meets the residency requirements on the date she applies.
The residency requirements are:
- she was physically inside the UK exactly 3 years prior to the date she submits the citizenship application (i..e if she were to submit on 1st April 2022, she must show she was in the UK on 1st April 2019)
- she has not been outside the UK for more than 270 days in the last 3 years, with no more than 90 of those 270 days in the last 12 months
