Ian,

When cold the standard guage should read 5.....i.e. lots of oil pressure. If it reads over the five matk then check that the engine is not over full with oil (check when engine is COLD and on a level surface).

When the engine is hot the guage should read about half way, droping to just over the red mark on tickover.......please note: near or just over the red zone on idle only!!! If it goes into the red during normal driving, then you may have a serious problem with your engine.