The last ten years has seen an explosion of literature looking at the role of real estate in a multi-asset portfolio. There has been a more limited development of literature in the UK and US which considers how real estate fits into an asset/liability pension plan framework. This paper considers further aspects of that problem. In particular, the range of available asset classes is extended to include UK equities, US equities, cash, UK government conventional bonds, UK government index-linked bonds and UK real estate. Results which suggest that a high real estate proportion is appropriate in a pension fund, because of the relationship of its returns with pension plan liabilities may not be valid when a greater number of asset classes with similar characteristics are considered. Secondly, our pension fund model decomposes pension plan liabilities into mature (retired) and immature (active) liabilities. These types of liabilities have quite different characteristics. We are therefore able to investigate whether the maturing of pension plan liabilities should have any impact on real-estate investment decisions.