Thomas Scarffe appears in the 1841 and 1851 (as Searffe) census. In 1841 all the Philips are nine years or more younger.
In 1851 his age is 51, which correponds to the christening of Philip and Jane's son.
No other children appear in the IGI for this couple. And the IGI has no other Phillip christening between 1795-1805.
Not only is there no marriage record for Philip and Jane to each other or to anyone else in the IGI, there appears to be no christening records for them either. So it is likely that the problem with the Lonan records is to blame. Another possibility is that they did not marry.