This just about says it all really

..and I am in complete ageement with Dr Evans on this, except that I would use even stronger language and go even further:

In view of these findings, it appears that attempts to extract pre-Synoptic and pre-Johannine forms of the tradition from Thomas and the other apocryphal Gospels surveyed above are speculative and precarious. Even more hazardous is the assumption that the existence of pre-Synoptic Gospels has been demonstrated. Extracting primitive, first-century materials or "texts" from second-century Gospels and making generalizations about the origins and theological tendencies of small scraps of papyri make for risky scholarship at best. At worst it constitutes special and an unobjective assessment of the evidence at hand. Aprt from the speculative reconstructions and imaginative contextualizations of Crossan, Koester, and others, there really is no evidence that any one of the apocryphal Gospels existed prior to the NT Gospels or that any one of the extant sources containes significant portions of one that did. Moreover, the evidence of individual sayings that may represent earlier and more primitive forms of tradition than what is found in the NT Gospels is also weak and far from conclusive.

Craig A. Evans. Word Biblical Commentary: Mark 8:27-16:20. Nashville, Tennessee : Thomas Nelson, 2001, xlii - xliii