Find your client, then select "Settings" and choose "Form access"
Note that, Form access can be restricted BUT not client details access.
Details access can only be controlled by setting up separate instances of LodgeiT , using Switch Organisation - DO NOT USE THIS FEATURE if you are NOT a Tax or BAS Agent. (check this link if you are Business Owner) ?
Adding organisation (multiple organisation) will require a charge of $300 per organisation and must have same ABN.