Charity Commissioners definition of religion

I'm chair of a small charity (Friends of Radosc, if you're interested - check us out on the charity commission website), and I've been doing a bit of reading about 'Public Benefit' - apparently to exist as a charity, we have to be able to demonstrate that we fulfil the requirement to provide Public Benefit.

The Charity Commission website indicates that one of the criteria for Public Benefit is 'The Advancement of Religion'. So we're OK.

It then goes on to define Religion:

The advancement of religion

20. For the purposes of charity law, a religion is a system of belief that has certain characteristics that have been identified in case law and clarified in the Charities Act 2006. Section 2(3) of the Charities Act states that:

"religion includes:

• a religion which involves a belief in more than one god, and
• a religion which does not involve a belief in a god"

So... my question is...

What about belief in just one God?

Does this definition tacitly exclude all the great monotheistic faiths?