I've managed to sort it now. I deleted my device, uninstalled Garmin Express and started from scratch. It now seems to be working great, I just make sure I open Garmin Express and select my Forerunner before I connect it. After a minute or so it then syncs and when I open Garmin Connect it appears there. I think I got confused because I didn't realise I needed to open my device on Garmin Express in order to sync it. I hope this helps you.