Readonly Login cannnot access user defined types

If using a program like crystal reports or similar to build reports using a read only account, the report builder will not give access to any columns which have user defined types attached to them.

To get round this, grant the following permissions to the user:

Use [Database]
GO
GRANT VIEW DEFINITION to [DW_Readonly]
GO

The VIEW DEFINITION permission lets a user see the metadata of the securable on which the permission is granted. However, VIEW DEFINITION permission does not confer access to the securable itself. For example, a user that is granted only VIEW DEFINITION permission on a table can see metadata related to the table in the sys.objects catalog view. However, without additional permissions such as SELECT or CONTROL, the user cannot read data from the table.

More details can be found here: http://msdn.microsoft.com/en-us/library/ms175808.aspx