There is an article here about the application of the Freedom of Information Act in universities. Michael Jubb, Director of the Research Information Network, discusses the lessons from Climategate and the Muir Russell report as well as looking at the ways universities would like the Act to be change.
There is discussion of extending the "Scottish exemption" to English universities. This exemption, which I'd never heard of before, would allow information to be withheld ahead of publication in a journal. I can't see anyone objecting to this. Data relating to unpublished papers would be of little interest to sceptics, since they couldn't be relied upon in the IPCC reports. That said, you would have to be sure that there was no question of withholding it further on the grounds that it was going to be used in another paper.
The other point to make is that (I think) this exemption would only apply to the FOI Act and not the Environmental Information Regulations, so would have little impact of sceptics searching for data.