Thanks for the inputs guys.
Ive ordered the unit off Amazon at £29.
Will run it side by side with iphone and see how accurate the data is.
For info I will be carrying out some surveys looking for, or activity of, water voles, Otter,mink and a few other species.
The little streams and becks are on forestry land so I need to record my data and finds accurately with photos.
Will feedback how I get on.