Will UK passport holders be required to self-monitor when traveling in and out of Thailand?

For UK passports will we be expected to self monitor if we travel out and then back into Thailand? I realise its meant for people travelling from the countries in the list but as we do not have stamps when entering and leaving UK and not all flights are direct from UK, I'm concerned as to whether all UK passports will be requested to self monitor. Is self monitoring just through the AOT app or do we have to do anything else? I travel in and out weekly, so concerned for general procedure