North plays in 3NT with the lead of the S7 from East, West playing the SJ and the SK winning.

I, Cliff Vince, foolishly did not count this properly at the table.  

The defence will probably play clubs when they get in next, since the other suits seem strong for Declarer. So you can count 2 spades, 3 hearts and 2 clubs.

You can set up 1 extra spade, but seem to need at least 1 diamond trick. Therefore at trick 2 you should not continue spades to set up just 1 trick, but rather lead a diamond to set up 2 or 3 tricks. East will play the DJ, and you are now fairly certain of 10 tricks.

Of course, West may have DAQJ. But even then, there is very little risk of losing more than 4 tricks. So the contract is assured.