  The majority of planetary nebulae (PNe) are not spherical, and current
single-star models cannot adequately explain all the morphologies we observe.
This has led to the Binary Hypothesis, which states that PNe are preferentially
formed by binary systems. This hypothesis can be corroborated or disproved by
comparing the estimated binary fraction of all PNe central stars (CS) to that
of the supposed progenitor population. One way to quantify the rate of CS
binarity is to detect near infra-red (IR) excess indicative of a low-mass main
sequence companion. In this paper, a sample of known PNe within data release 2
of the ongoing VPHAS+ are investigated. We give details of the method used to
calibrate VPHAS+ photometry, and present the expected colours of CS and main
sequence stars within the survey. Objects were scrutinized to remove PN mimics
from our sample and identify true CS. Within our final sample of 7 CS, 6 had
previously either not been identified or confirmed. We detected an $i$ band
excess indicative of a low-mass companion star in 3 CS, including one known
binary, leading us to to conclude that VPHAS+ provides the precise photometry
required for the IR excess method presented here, and will likely improve as
the survey completes and the calibration process finalised. Given the promising
results from this trial sample, the entire VPHAS+ catalogue should be used to
study PNe and extend the IR excess-tested CS sample.
