Platanthera Orchids on the Caledonain Canal

A pleasant day walking along the Caledonian Canal with great views of the north side of Ben Nevis was given a real boost when I came across an orchid that I'd never seen in the wild before. I'd seen lots of common spotted orchid of various colours in the hay meadows in Glen Nevis and there were both pale and dark ones along the canal side but a white one caught my eye and on closer inspection I realised that it was quite different. Looking it up it appears to be a Platanthera (Butterfly orchid) but I'm not sure if its the greater or lesser variety.