Thanks @lowdown, I've adjusted the buffer size. The latency shown on the interface window is significantly lower, and the issue I had seems to be less though not completely eliminated when playing an instrument on an audio track (I can see it on the audio track but not really hear it).
Somewhat strangely there is no global defeat for the Latency Compensation - it's described in the manual and I just can't find it on a toolbar but I did find it on the track window where you pointed to. Possibly because I have a cheapo version of Cubase. Even stranger, with the latency compensation defeated anything played via the midi port is defeated so it looks like the compensation is double what it should be. I can live with it on the MIDi as I don't do anything too complex and can shift the notes manually or via the track delay function.