I wouldn’t plough all the money in there unless you really understand what you’re doing. If the company went bust you’d lose all your money.
Premium bonds just lose money all the time as the wins don’t keep up with inflation.
Have a look at ISAs. Under that wrapper, you pay no tax on your gains. You can buy funds. Funds are run by fund managers who invest people’s money into a range of things, eg shared in 100 different companies. Even if one goes bust, others might do well and you’re still earning. However, there will be some fluctuations. The funds are designed to offer different risk levels and types of investments (eg small businesses in SE Asia vs large U.K. companies etc). You can always pick one or a few to suit the type of investor you are.
You can get funds from local banks but you can also set yourself up in websites such as YouInvest or Hargreaves Lonsdown. If it feels overwhelming, then seek advice from an Independent Financial Adviser.