Premium bonds

I am finding that the money I have invested in Premium Bonds is giving me an excellent return, much better than the money I have in my savings account. ERNIE comes up most months. I have the full amount one can own in Premium bonds, and my three daughters have kindly said I can put the full amount in their names too, on the understanding that if ever I need it they will withdraw it for me. Obviously I tell them to keep any prize money.