When you sell the house the money you have left over is not taxable as CGT but you may have to pay tax in other ways depending on where you chose to put it.
If you put it into a pension you actually get tax relief off the taxman,which is free money. But you will have to pay tax on your pension when you draw it in the same way as you pay tax as an employee. You can pay 100% of your earnings into your pension per year,so you can't necessarily put it all in a pension in one go.
If you put it into a savings account you will have to pay tax on the interest assuming you are a taxpayer.