Access denied by Business Data Connectivity when trying to add myself to the BDC Metadata Store

Originally I was trying to create a ECT in SharePoint Designer 2010, on the production server, and every attempt fails with the error "Access denied by Business Data Connector" and I found the post "Deploying a BDC Model project to SharePoint 2010" which suggests that I may not have rights to the BCD Metadata Store: "It seems that an account are you using to deploy solution doesn't have sufficient permission in the BDC Metadata Store."

So I tried to set myself (individual windows user) up to have rights via:  "Central Administration->Application Management->Manage Service Application->Business Data Connectivity Service->Click Set Metada Store Permission on the ribbon->Set Permission you need and tick the checkbox "Propagate permission to all"; and pressing the OK button an error dialog displays stating Access denied by Business Data Connectivity.

What should I check next?