What is the full second-hand value of Gillian's watch?

The full second-hand value of an item like Gillian's watch typically refers to the price it can fetch in the resale market. In this context, the correct choice of £4,000 suggests that this amount accurately represents the market value while considering factors such as brand, condition, demand, and comparable sales.

For luxury items, second-hand values can vary significantly based on these factors, and it's essential to reference market trends or specific platforms specializing in second-hand luxury watches to determine an accurate value. The correct answer indicates that £4,000 is likely reflective of such considerations, making it the most plausible figure among the provided options.

The other amounts may not align with realistic market expectations, either appearing too high or too low given the context usually surrounding the resale of luxury watches. Therefore, £4,000 stands out as the most reasonable second-hand value in this scenario.