@Boydie @MrBouzouki @Jambrains @adamfarr Thanks for the responses, they were interesting.
There's a really useful too for Windows pcs called Plugin doctor, it tells you in a graphical representation what your plugin does to your sound, even with the knobs set to flat, you'd be amazed, I cant remember if it's free or not, but it's quite revealing, and can scare the living daylight out of you, or give you a lovely feeling of warmth and Yeah I'm right about that....
Here's what it does. But let your ears be the final arbiter of what sounds right, just because it mangels the curve, doesn't mean it's wrong.
My current favourites are the stock Samplitude meters, SPL Hawkeye and Metric Adaptr AB, I have these 3 open and between them they tell me what I want to know, but these only tell me what my ears cannot.
Other notable mentionsYouLean pro is also excellent, I wish all metering plugs were available as stand alone with drag and drop.
Mastering the Mix - Expose is also useful