Especially that last few lines I'm here to tell you.

Well submit some vagy vids if you're tired of turgid trouser trout tales.

There must be a written form, perhaps in old Wodehouse novels.. that semi-laugh semi-chuckle of the cultured middle class.. I don't think onomatopoeia exists for it. Ehgehueghueghuhuhu?

he says "uhhhmthankyouverymuch"

really

oh I see you were referring only to the "uhhhm"

search me, but it does seem to be some kind of british, class-institutionalized verbal prelude to whatever is spoken next (usually very quickly)

of course if they just make that noise and then stop, it's the upper class twit of the year award