I have all 4 sensors off the car, cant see anything wrong. error code is saying the right outer is at fault.

 

when i put the car into reverse i get a bleep and then the reverse sensor logo appears for a second or two on the dance, then a louder bleep and the logo dissapears.

 

does this mean that the car has stopped park sensing all together? and gone into a fault mode so none work?

 

How do i test wiring and sensors on the bench? anyone got a diagram?

Well there is a supply lead, an earth return lead and a signal lead, so all the supply leads get commoned as do all the earth return leads.  Have you tried swopping right outer to left outer to see if the error code moves with the sensor, if so it is duff and you need to buy a new one maybe from ebay, normally there are genuine ones there for pleasant prices.