The player  who played this hand against me not only could not bid properly but then went onto to completely misplay the hand too.

In order to make 3NT you will need to get those lovely Hearts going in dummy. However you only have two entries outside the Heart suit and the opponent has already forced out the Club Ace so in reality you only have the the ♦K

Your Hearts are magnificent and overtricks are not important. Without dong any work at all you have 1 Spade winner, 2 Heart winners, 2 Diamonds and 1 Club. You only need to generate 3 more tricks. You can afford a Heart loser and still be OK.

With all this in mind, and a shortage of entries win the second club pleased to see the Jack being played and now you might have an extra Club winner too, you win second trick and play dummy's Ace of Hearts dropping your queen and being in right hand to continue playing hearts. East takes the second Heart and switches to Spades. Since you are playing IMPs, where making the contract is more important than any overtricks you take the Ace. You enter dummy with the Diamond King (your only entry) and play off all your established Hearts. You now just take your winners and make exactly 9 tricks. If you had been playing Match Point Pairs where overtricks are important at the 11th hour you might finesse the Diamond and then  you will make 10 tricks.