High inflation makes it hard for firms and individuals to distinguish changes in the relative prices of particular items from generalchanges in the average price level, so price signals become blurred.
If margin rule changes for a minor commodity can trigger a generalprice run, imagine what would happen if a series of broad based rule changes were implemented.
If house prices in general are moving in line with the price of a typical house, this approach gives a good guide to changes in housing wealth, which is what matters for the Bank of England as it assesses the economy.