As stated on the home page of “The Devon Wills Project” at Origin.net:
”The majority of wills and administrations of Devon people were proved or granted in either in Devon itself or in London. The originals of those wills proved in London (very nearly all at the Prerogative Court of Canterbury, "PCC") have survived. However many probate records for the county of Devon and Diocese of Exeter including the Exeter Principal Registry were destroyed by enemy action in 1942, when the Probate Registry was destroyed in the bombing during the Exeter Blitz of WWII. Thus the overall aim of this index is to create a finding-aid to enable the researcher to determine what probate materials were originally recorded and most importantly what documents have survived (original document, copy or abstract) and where they can be located.”
The link below will take you directly to a search form.
Origins.net - National Wills Index - Search Devon Wills Project 1312-1891