when is the date in the month to invest in premium bonds. your debit card takes 7 days to clear and your investment is entered in the draw after a full calendar month?
If you buy at a post office you don't have to wait for your money to clear. So if you buy on the last day of May,then they will be entered into the July draw - and every draw from then on.
I have just checked my premium bonds (no luck this month - May) and this is what they say about checking previous draws:-
"The Premium Bond prize checker shows any prizes you may have won in May and the past six draws, along with any prizes unclaimed from previous draws. We normally update information on prize-winning Bonds by the third working day of each month"