If you have been out of the UK for two years or more, you have to demonstrate why unless you fall under one of these categories:
- a permanent member of the Diplomatic Service
- a UK-based British Council employee who works outside the UK
- a Department for International Development (DFID) employee
- a Home Office employee
If not, certain rules apply and they include
Para 18 - An individual seeking leave to enter the UK as a returning resident may be admitted for settlement provided the Immigration Officer is satisfied that the individual applying concerned:
- had indefinite leave to enter or remain in the UK when he/she last left; and
- has not been away from the UK for more than 2 years; and
- did not receive assistance from public funds towards the cost of leaving the UK;
and
- now seeks admission for the purpose of settlement.
Para 19 - A person who does not benefit from the preceding paragraph by reason only of having been away from the UK too long may nevertheless be admitted as a returning resident if, for example, he/she has lived in the UK for most of their life.
To prove why you were out of the UK for two years of more can be very complex, but not impossible if you can show exceptional circumstances and this will include evidence of how long you lived in the UK, provide evidence of UK employment, paying taxes, studying, UK residence such as GP/Dentist appointments, hospital visits/operations, basically legal documents to show you were 'present' in the UK. Just to say I own a home, does not mean you lived in the UK during that period.
If you cannot prove the above, you maybe required to apply for a new entry visa to enter the UK.