In a national economy, the money supply ($M$) is initially £400 billion, the velocity of circulation ($V$) is constant at 5, and the real national output ($Y$) is 1,000 billion units. The central bank then increases the money supply by 20%, while technological advancements cause the real national output to grow by 25%.

According to the Fisher equation of exchange ($MV=PY$), what is the new general price level ($P$)?