I registered for this and accessed the site list and hourly data using the xml feed and my API key - not too difficult if you scan the documentation
Although the site list contains 6,000 stations only about 140 of them are available for free downloading of hourly data as you describe
Basically all the sites with WMO refs 3000-3999 plus just 4 others in the 99xxx range (Woburn, Scarborough, Stonyhurst, North Wyke)
Digging around a bit, I think the data exists on an hourly basis for many of the other sites but the Met Office have decided to make this only available at a fee (£500-£2000pa per "bulletin") which is a great shame IMHO
So my conclusion is that for smaller sites like Kew Gardens, Brampton and some of the Edinburgh ones there is no longer any public access to this hourly data anywhere
Unless anyones knows differently 
Originally Posted by: lanky