The fair value of completed investment property is determined using either the discounted cash flow or traditional method. Discounted Cash Flow method is based on the future annual net operating income over a hold period of 10 years. Growth and inflation are included explicitly in the cash flow forecast. The valuer calculates the present value of cashflow generated by the investment property plus the present value of the exit value at the end of the 10-year hold period. The cash flow is discounted at a rate the valuer considers appropriate for the specific investment property. Where known, the property valuer takes account of deleterious materials included in the construction of the investment properties in arriving at its estimate of fair value when the Investment Manager advises of the presence of such materials. The majority of the leases are on a full repairing and insurance basis and as such the Group is not liable for costs in respect of repairs or maintenance to its investment properties. The traditional method requires an assessment of rental value (the market rent) and a market-based yield. The yield can be simply defined as the annual return on investment expressed as a percentage of capital value. The traditional method can reflect income streams which are under-rented and over-rented by incorporating risk within the yield choice (i.e., an all risks yield) and by structuring the calculation appropriately, for example a term and reversion for under-rented income streams and a hardcore and top-slice for over-rented income streams. This will require the valuer to reflect risk in each element of the calculation, e.g., increasing the yield <mark style="background-color:yellow">above</mark> the market in the top-slice to reflect the added risk of an above market rent being paid for a specified period, or reducing the yield in the term to reflect that a below market rent is being paid until the reversion is due. These traditional approaches are typically referred to as being growth implicit, meaning that rental growth is built into the choice of yield and not explicitly modelled within the calculation. As at 31 December 2022 the German, French, Polish and Spanish assets were valued using the discounted cash flow method, and Netherlands properties using the traditional method. The fair value of investment properties amounted to €758,719,000. The difference between the fair value and the value per the Consolidated Balance Sheet at 31 December 2022 consists of adjustments for lease incentive assets and the Den Hoorn lease liability separately recognised in the balance sheet of £4,740,000 and £22,637,000 respectively. Further details of the Den Hoorn lease are disclosed in note 12.