Just wanted to come back and confirm that I contacted Qatar and have had this response from Qatar Customer Care.“We remain seriously concerned to note of your experience wherein you have not been able to access the lounge provided that you were traveling premium class on a redemption ticket.

While our staff members, both on ground and in flight are trained and entrusted to deliver outstanding levels of customer care, we take reports such as yours with serious concerns in our desire to provide the best possible service and continuous improvement.

This matter has been brought to the attention of our ground services management in Edinburgh and necessary corrective action were already taken.”

Hope this might help if anyone else ends up in the same position.