It's a faff, but diligent record keeping by you would be needed in case DWP requested it. Separately, if you live outside the UK, and in another state, for more than (I think) 180 days then certain 'tax residency' rules would be triggered which may affect how or where you may need to file an annual personal tax report.

Off topic re the original question / post but relevant to the UK pension increase question. The UK, and Thailand, have treaties in place with various countries that permit people of pensionable age and receive increases. Unfortunately there is no arrangement between the UK and Thailand. If a UK citizen, who is eligible for a state pension, lives outside the UK for more than 180 days each year, this triggers an overseas eligibility check. If the person lives in a country, such as The Philippines, where a treaty is in place to allow them to receive any statutory increase in the pension, then the person will continue to enjoy the same state pension as someone who remained in the UK. Living in Thailand for no more than 180 days each year, and either returning to the UK for the remainder or sharing the remaining time between countries that have a treaty in place (which doesn't necessarily need to include the UK) that has a 'pension equivalence' treaty (quoted words are mine) would allow you to receive any annual increase in state pension.