Thanks Marco,
so I tried again, NB you need a & before that scope so
curl -X POST -d "granttype=password&clientid=<clientidhere>&clientsecret=<secrethere>&username=<usernamehere>&password=<passwordhere>&scope=readstation" https://api.netatmo.com/oauth2/token
but I get "invalid_grant"
my post is like
curl -X POST -d "granttype=password&clientid=AAAAAA&clientsecret=BBBBBB&username=user+extra@ISP.com&password=XXXX&scope=readstation" https://api.netatmo.com/oauth2/token
could it be the + I use in my email address