Logging in to My Garmin in Basecamp

Have purchased a 1500 sq km tranche of Birds Eye Select GB. Have activated the purchase and the credit is shown in the Basecamp installation pop up window. However every time I try to log in to Basecamp to effect the download the verification of My Garmin account fails with the message that User ID or PW is incorrect. I'm using the exact same info to log in to My Garmin account in my web browser without problems! Seems to be a Basecamp issue - anyone experienced the same and found a solution? Using Basecamp 4.4.5 with OS X 10.10.1 Yosemite. Thanks....