  Central exclusive double diffractive Higgs boson production, p p \to p + H +
p, is now recognised as an important search scenario for the LHC. We consider
the case when the Higgs boson decays to two W bosons, one of which may be
off-mass-shell, that subsequently decay to the q qbar l nu final state. An
important background to this is from the QCD process g g \to W q qbar, where
the two gluons are required to be in a J_z=0, colour-singlet state. We perform
an explicit calculation and investigate the salient properties of this
potentially important background process.
