  The Wide Field Camera Transit Survey is a pioneer program aimed to search for
extra-solar planets in the near-infrared. The standard data reduction pipeline
of the program uses aperture photometry to construct the light curves. We
alternatively apply the difference imaging method for the most complete field
in the survey and carry out a quantitative comparison between the photometric
precision of both methods for objects with J<18. We also report an
implementation on the box-fitting detection algorithm, which performs a
trapezoid-fit to the folded light curve. Subsequently a set of selection
criteria are optimized and applied to the light curves to search for transit
candidates, incorporating a parameter to characterize the shape of the transit.
We carry out a detailed analysis in the 18 best detections and classify them as
transiting planet and eclipsing binary candidates. One planet candidate
orbiting a late G-type star is reported. No planet candidate around M-stars has
been found, which enabled us to set an upper limit on the occurrence rate of
short period giant planets around M-dwarfs in the survey of 1.1%. Furthermore
we report the detection of five faint extremely-short period eclipsing binary
systems with periods shorter than 0.23 days and three candidate M-dwarf/M-dwarf
eclipsing binaries. The detections demonstrate the benefits of using the
difference imaging light curves especially when going to fainter magnitudes.
