CZ,
Yes the 5 landings must be full stop (and taxi back) but after that you can do what you want, you dont have to go dissappearing off into the night if you dont want to. You can quite happily bum about in the circuit until you fall out of the sky with boredom
I spent my 2 hours doing a combination of this and flying off to the practice area for a bit of fun and then trying to find the airport again on the way back.
Some airports however wont let you do TnGs at night (mainly due to noise abatement) so best check before you do or you may upset them.
Still think flying at night is some of the nicest to do, very quiet on the radio and generally pretty smooth. Have fun!
Julian.