Nice pictures Dave, I've never been up there when it is flowering. It looks like Myosotis 'Mossburn' (Naturally Uncommon), there is no fact sheet for it on NZPCN because it is not a formally named entity. It gets a nice tinge to it over the winter as per this photo taken in September. Where your photos taken on Black Ridge? Pretty spectacular place, eh? There are some other neat things up there too including Cardamine sp. 'calicole', Carex uncifolia, Celmisia spedeni, Oreomyrrhis basicola and Brachycome sp. 'West Dome'.
Here's a panorama we shot up there (not plant related, I know, but most forum members will probably appreciate the view!). http://www.cerulean.co.nz/west-dome/