AnneElliott if you have your details you just set it up to notify you by email on the ns&i website . You can otherwise easily check with your holder’s number on the website (I did this this month as its quicker and I’d won £100).
i also have set mine to pay any wins back into the account as you can choose to do this.
i won £25 3 or 4x times this year with about £2k in PB and I increased it last month. I find it both reassuring to have savings I try not to touch so there for emergencies and enjoy the idea of wins but I don’t think too much about it