'Semi by the sea'?

What kind of 'semi'?

James Blunt:

WISE MEN

She said to me, "Go steady on me.
Won't you tell me what the Wise Men said?
When they came down from Heaven,
Smoked nine 'til seven,
All the shit that they could find,
But they couldn't escape from you,
Couldn't be free of you,
And now they know there's no way out,
And they're really sorry now for what they've done,
They were three Wise Men just trying to have some fun."

Look who's alone now,
It's not me. It's not me.
Those three Wise Men,
They've got a semi by the sea.
Got to ask yourself the question,
Where are you now?

Really sorry now,
They weren't to know.
They got caught up in your talent show,
With you pernickety little bastards in your fancy dress,
Who just judge each other and try to impress,
But they couldn't escape from you,
Couldn't be free of you,
And now they know there's no way out,
And they're really sorry now for what they've done,
They were three Wise Men just trying to have some fun.

Look who's alone now,
It's not me. It's not me.
Those three Wise Men,
They've got a semi by the sea.
Got to ask yourself the question,
Where are you now?