Do I need to show a return flight within 60 days for a METV visa application?

Hello.

I am planning to get a METV six month visa from the London Thai Embassy in January.

I plan to have a return flight returning around six months later with a flexible ticket.

Do I need to show a return within 60 days or will they be fine with a return flight six months later?

I have been to Thailand three times previously but only on Visa Exemptions for less than 30 days.

Thank you