Nature has the story, here. Apparently, one of the advisers to the project, which was designed to inject sunlight-reflecting sulfur aerosols high into the atmosphere, has filed a patent claim for the method (which is depicted in the story). Aside from the evident conflict of interest, I have my doubts about the novelty of technology for receiving a patent. I'm no expert in patent law in the US, let alone in the UK, but I don't see anything in the process that appears either novel (aside from the application of old technologies to the new geoengineering purpose) or non-obvious.
The more interesting aspect of the decision to postpone or cancel the demonstration project for me was the project leader's suggestion that more of an institutional framework was required to govern such experiments: "Although 'it is hard to imagine a more environmentally benign experiment', in the absence of an agreed architecture, Watson said that the field trial would be 'somewhat premature'.