Do we need two financial letters from the British Embassy for a joint retirement visa extension as a married couple in Thailand?

The question revolves around whether a married couple applying for a retirement visa extension in Thailand needs one or two consular letters from the British Embassy to confirm their joint income from a UK bank account. Various comments indicate that generally, only one letter is needed for couples as they can 'piggyback' on a spouse's financial proof if they meet the combined income threshold. However, due to inconsistencies in immigration office practices, the poster is uncertain and seeks clarification on embassy requirements and payment for the letters. The thread highlights the complexities and varying interpretations of visa requirements and procedures.