The office block owned by Al-Taweel Establishment, which has been held as an investment property for many years and is now intended to be sold, would typically fall under the definition of an investment property under IAS 40, Investment Property. This standard defines investment property as property (such as an office block) that's held to generate rentals or for capital appreciation, rather than for use in the production of goods or services, for rental to customers, or for administrative purposes.

Given that management has committed to selling the office block, but it is unlikely to be sold in its current state due to the significant price gap compared to its fair value, it does not immediately meet the criteria for held for sale under IFRS 5, Held for Sale Assets, as that classification requires that the asset is expected to be sold within one year and that the sale is highly probable. Since the property is not expected to sell at its current market price, it doesn't satisfy the "sale within one year" and "highly probable" conditions.

Therefore, based on the information provided, the most appropriate classification for the office block would be:

It is an investment property.

This classification could change if and when the circumstances around the planned sale evolve, such as receiving a binding offer at a price that indicates a sale is highly probable and expected to occur within one year. Until then, it remains an investment property.