Night stuff is a good thing to do in a sim ..... as high-resolution external graphics are not one of the things you get included in your multi-million pound simulator, so day VFR is pretty basic.

If you want to do some circuits and night (or day) VFR approaches, get them to set you up somewhere "interesting" rather than LHR after the first circuit or two. After the demise of Kai Tak (I believe it's firmly deleted from the sim database these days), there are not many places left that are so extreme, but there are a few spots that have either short-ish runways or tricky noise abatement profiles.

Don't forget to check the training screens to see how stable your approaches were ! ;-) (they'll probably show you anyway as part of the experience)