You can apply for ILR under the long residence route up to 28 days before you meet the 10-year continuous residence period. It is important not to apply too early as there is a chance of refusal if the Home Office calculate that you don’t quite yet meet the requirement. It is always advisable to check with an immigration lawyer before you submit your application to ensure that you have worked out your period of residence correctly.
Your application for 10-year long residence ILR can be completed online on the UKVI website. You will need to pay the application fee of £2,404, however, you will not be required to pay the healthcare surcharge as you will have full access to the NHS as a settled person. During the application process, you will be asked to book and attend an appointment at a local UKVCAS service point to have your fingerprints scanned and your photo taken (your biometrics). UKVI will also request a number of documents to prove your eligibility for long residence ILR, including your current passport and all other passports held while in the UK and your current biometric residence permit (BRP).
Once you have completed the above steps, you will normally receive a decision within 6 months. If you require a faster decision, you may be able to pay an extra fee of £800 for the super-priority service, which will provide a decision by the end of the next working day.