Non Imm Type O, Re-entry Stamp?

[JCCR6]

I've got a Multiple Entry Non Immigrant type O visa from the nice people at the Thai Consulate in Hull (UK), I'm approaching my first 90 day visa run. Just a quick check, do I need a re-entry stamp/form? I don't want to leave the country and then find out I've invalidated my visa etc.

[lopburi3]

No. A re entry permit is only required to maintain a permitted to stay stamp or an extension of stay issued by immigration.