Gentlemen, Thanks for your help. Problem solved.

The solution was actually staring me in the face. Open Enterprise Manager, select the CORRECT server...:sick:

Sincerest appologies

Refreshing the individual database or all databases has no effect. The permissions have still not been applied.

Tried enclosing [Domain\UserName] but that returns a syntax error "There is no such user or group 'Domain\UserName'".

Username is returned from sysusers exactly as expected "NPQuiggin"

Running sp_grantdbaccess @loginame = 'Username' tells that UserName does not exist. If I qualify it with a domain then it tells me that UserName already exists - that is...