You can use council tax or letters from other government agencies (eg DVLA, electoral register, HMRC). Tax assessments are not proof of residence, and I doubt letters from clients would be accepted.
Review
https://assets.publishing.service.gov.u ... t_2023.pdf page 33
Absences
You should supply the following documents to show you have been mainly in the UK
during the 5 years (or, if married to or in civil partnership to a British citizen, 3 years)
before making your application:
• Your passports
• If you are unable to provide your passport, explain why and supply letters from
employers (including start and finish dates), payslips, P60s, educational
establishments or other government departments indicating your presence in the
United Kingdom during the relevant period
Examples of documents that can be used to show you have been in the UK for the
required time period, can be found here.
Although we do not normally accept doctors’ letters on their own as proof of presence,
these may be accepted if nothing else is available and the doctors can confirm that they
have seen you on a regular basis during the period concerned.
If your passport is not stamped when you come into the United Kingdom, you must still
provide your passport, but also provide alternative evidence of presence as above
All advice comes from personal research and experience and should not be regarded as professional opinion.
