You may or may not know that when you make personal contributions to pensions, you get tax relief up to your highest rate of income tax.
If you earn £160,000. You are paying 20% income tax, then 40% income tax and 45% income tax on income above £150,000. £10,000 is taxable at 45%. If you make a gross pension contribution of £10,000 you will get 45% income tax relief on the £10,000 paid i.e., tax relief of £4,500 meaning you have paid just £5,500 to have £10,000 extra in your pension fund.
For the same person above, if they pay £15,000 gross into a pension, they will get 45% tax relief on the excess income over £150,000 i.e., that which has paid 45% income tax and the other £5,000 gross pension of the £15,000 total will get 40% income tax relief.
Therefore, you need to consider making pension contributions in the current tax year to attract higher rates of income tax relief as they reduce next year.