We have ALL our savings, (£35,000), in Premium Bonds.
So far this year we've won £25 in January, and £25 this month. I signed up for email notification, and for winnings to go directly into our bank account, as opposed to a cheque in the post.
I'm able to see anonymised details of where winners live, how much they have invested, and how much they have won. I'm afraid the big prizes are largely won by people who have the maximum holding of £50,000.
I haven't bothered to analyse the numbers, but I would say that roughly at least 75% of the big winnings go to people with the maximum holding - which is logical I guess, but a bit disappointing for the rest of us!