For this cache, you will want to head down the ballymacormick road near the groomsport roundabout. Down near the bottom of the road you will see a couple of places that you can park and gain access to the field were the cache is located.
Cache is small but you should be able to find it. You might need a pair of tweezers depending on what way the previous person puts the log back in place.
Its quite open, so you will need to be quick to avoid being spotted!