If an agent provides a customer with overseas accommodation or car hire in addition to a flight inclusive package (if requested at the same time or within a day), this will be classed as Flight-Plus and require protection under the agent's ATOL. ATOL holders may not be aware of this happening and thus they should continue to issue an ATOL Certificate for the package. However, the agent will not be required to pass this on to the customer, but will be obliged by the ATOL Standard Terms to pass on the Confirmation for the package.
If an agent adds another tourist service such as attraction tickets or airport transfers to the package, this would not be classed as a Flight-Plus and is simply sold in addition to the package.