This cache is placed in a spot in Denbigh that has few caches now that some have been archived. Originally placed by biggles1234, the cache has been adopted by Fairllis and the container has had a face lift which will hopefully reduce the maintenance needed. Please be careful when replacing the cache container, and ensure the lid is good and tight.
St. Marcella’s (or Llanfarchell) is also known as Whitchurch or Eglwys Wen - ‘the white church’, probably from its originally whitewashed exterior. Its patroness Marchell the Virgin is said to have established her hermitage by a holy well here in the 7th century, and clearly the site was honoured as especially sacred. For though it now stands alone a mile from the present town centre (and further still from the old walled town by the castle), St. Marcella’s has always been Denbigh’s parish church (more detail of the history can be found here).
The cache is a micro and can be found by the gate leading to the sewage plant on the drive behind the church. Bring a pen and your thinking cap! 
Take a moment to enjoy the views of the Clwydian Hills and if you are there on the first Saturday of each month 10.00 am - noon, Easter to October inclusive you can go in the church and have a look.
FTF - but who was it?
Mystery solved! Looks like it was searcherdog. Congratulations!