It looks like Google UK are doing some funny stuff with sitelinks. Early in march a few people noticed that the typical site links, two columns of up to 8 extra links under the top listing for a search result, which looks like this
Google Site Links
They changed this to a single line for some results, in fact it seems for results in position two, here’s 2 examples.
One Line Site Links When no Sitelinks for position 1
And this where there are sitelinks for position one and two.
Sitelinks for position 1 and 2
If you are wondering if you like either, none or have no opinion think again, you really should like having both, big sitelinks and single line sitelinks for position 1 and 2, as in the last example.
Why? Because it takes up more browser real estate and as they only appear if you are the absolute result for a search term, such as your brand name, then this helps you dominate the results page, this is good, as it equals more clicks.
However, it is interesting that the middle screen grab above shows sitelinks for position 2 but not for position 1. Lets put this down to testing.