The ST50 is no longer supported. You can buy an ST60 masthead unit for about £200 or I have a spare ST50 unit you can make me an offer for. It will be missing the wind direction vane, but all the internal electronics and the windspeed will be there. Just swap your wind direction vane onto this one with a 1.5 mm allen key.
-------------------- “When you discover that you are riding a dead horse,
the best strategy is to dismount.”