Vignoble Limited $($Vignoble$)$ is a wine$-$making company that produces and sells premium and everyday wine. It operates vineyards and wineries in Australia and New Zealand and exports to international markets, particularly in Asia and the United States. Vignoble has two cash$-$generating units $($CGUs$)$: Estate CGU, which sells the everyday wine brands; and Premium CGU, which sells exclusively premium wines. In August $2024,$ one of its largest international markets announced the immediate introduction of a $200\%$ tariff on wines imported from Australia. To maintain its profit margins, Vignoble passed the tariff costs directly to its customers through higher prices. This has led to a significant decrease in sales revenue for both CGUs but particularly for the Estate CGU, as consumers of the everyday wines are more price$-$sensitive when compared to consumers of premium wines. To mitigate the impact of the tariff, Vignoble accelerated its efforts to expand into other markets but has been unable to quickly establish new markets and new customers. The reduction in sales has led to an increase in inventory and increased warehouse storage costs due to the unsold wine in both CGUs. Following the challenging market conditions, Vignoble$$s board is reviewing its operating profit expectations for the next three years, which are significantly lower than was anticipated $12$ months ago. It is also exploring opportunities to scale down Estate CGU production, which has been more heavily impacted by the tariff, and focus on selling its premium wines. Additional information $$ The Premium CGU correctly includes the recognition of an asset for the iconic Noble Vintner brand of luxury wine, which was purchased in a business combination over twenty years ago. The brand name has been assessed as having an indefinite useful life as it is expected to generate cash flows indefinitely, in conjunction with the other assets of the Premium CGU, given its strong market presence and brand recognition. There is no active market for the Noble Vintner brand name. $$ Other assets in the Premium CGU include trade receivables, inventory, plant and equipment used in wine production and distribution. Required $($a$)$ With specific reference to IAS $36$ Impairment of Assets, identify and explain one internal and one external indicator of impairment for the Estate CGU at $30$ June $2025.$