Try to use registry key for the setting of "Trust access to Visual Basic project" - AccessVBOM

Note: Microsoft documentation mentions Policies >> Software\Policies\Microsoft

This is for Macro Security set to Medium (same applies for all 3 as below)
Registry Settings
System Key: [HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security]
Value Name: Level
Data Type: REG_DWORD (DWORD Value)
Value Data: 2 (0x00000002)

This is for Default User
Registry Settings
System Key: [HKEY_USERS\.DEFAULT\Software\Microsoft\Office\11.0\Excel\Security]
Value Name: AccessVBOM
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = uncheck the checkbox, 1 = check the checkbox)

This is for Current User
Registry Settings
System Key: [HKEY_CURRENT_USER\Software\Microsoft\Office\11.0\Excel\Security]
Value Name: AccessVBOM
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = uncheck the checkbox, 1 = check the checkbox)

For All Users (option becomes greyed out)
Registry Settings
System Key: [HKEY_LOCAL_MACHINE\Software\Microsoft\Office\11.0\Excel\Security]
Value Name: AccessVBOM
Data Type: REG_DWORD (DWORD Value)
Value Data: (0 = uncheck the checkbox, 1 = check the checkbox)

Enforce settings by using Group Policy in the 2007 Office system

!!! Check Excel ADM File for AccessVBOM / Alert for unsigned Macros - Should be Security not Options !!!
Office 2003 Service Pack 3 Administrative Template (ADM), OPAs, and Explain Text Update

2007 Office system (SP2) Administrative Template files (ADM, ADMX, ADML) and Office Customization Tool

Office 2010 Administrative Template files (ADM, ADMX/ADML) and Office Customization Tool download