Just to draw attention to this, as deadlines are approaching. Briefly, more than twenty selected UK charities doing work overseas run a specific UK Aid Match campaign over a period of not more than three months between September 2016 and March 2017, and the Department for International Development matches contributions to them 100% (but excluding the Gift Aid benefit).
I'd not been aware of this before, even though there seem to have been various rounds of it since 2013. I only learned of it from Sightsavers, whose own campaign runs until 8 January. But they're clearly all of limited duration, and nearing their deadlines if not already there. You can see more details and a list of the charities involved in this round at [www.gov.uk
I'm a little annoyed I dodn't know about it earlier. It's a lot more beneficial than the Gift Aid scheme (which I trust also applies). If donating, note that it's only contributions given to an appeal clearly advertised as participating in UK Aid Match that will benefit from the matching.