my parking sensors only work sometimes any idea

 

Possibly one or more sensors on their way out or dirty?
when it doesn't work do you get a tone?
Mine didn't work when i got it, I tested them By putting it in to reverse with ignition on and then if you listen up close to each sensor, you should heat it tick repeatedly. On mine both outside sensors weren't working so took them off and cleaned them and the connectors and now working like charm.

 

If you put your finger on them lightly, you can also feel them giving a slight buzzing feeling, that's how I found my dead one.

 

Welcome to the forum chooseysuzy,

Please post an intro in the new members section when you can.

Is this an S Type?
Check for water in the spare wheel well in the boot.