If you and the missus are a high rate and basic rate tax payer respectively you can save £30k between you @ 5% before paying tax.
A lot more savings interest is tax free if your missus earns less than £17570.
If you have a Barclays current account, you can earn 5.12% on saving up to £5k.
Max that out over time and then move the £5k into a bond. Rinse and repeat.
https://www.moneysavingexpert.com/sa...best-interest/