Tuishimi, on 15 November 2012 - 15:41, said:
Are they hard-shelled or leathery. If leathery then they are snake or turtle eggs. If they are hard-shelled then they belong to a bird of some sort.
You might want to either put them back or build a make-shift incubator for them.
There aren't really any wild snakes or turtles in the UK
On a serious note, I suspect finch or swallow eggs. Mind washing them a little with water to get the dirt off and photographing them from closer up on a white sheet? Perhaps put some reference object next to them, a ruler or a coin.