S-type steering lock will not engage

Hi I am new on here having bought my first Jaguar last week .I put it in for a roadworthiness test and it failed .The main failure that has me puzzled is that the steering lock makes a whirring noise when you put in the key but when you take it out the wheel still turns .Thanks for any replies in advance .

Managed to sort it out with a little help from posters and a lot of luck.