If we give you permission to enter for less than 6 months, and you later want to extend your stay to the maximum of 6 months in total, you must apply for an extension - see below.
oh okay I get it now... I didn't think that UKBA gives visa for less than 6 months..
-=rayna.keith=- ...When you realize you want to spend the rest of your life with somebody, you want the rest of your life to start as soon as possible...