I think this topic is important enough to risk sowing the seeds of more confusion!!
In general, I agree with Pete and others, about the colour gradations of 'typical' skipper antennae. HOWEVER, this individual exhibits some melanism and this is reflected in the continuous dark of the antennae as well as in the wings. Essentially, she has more black pigment all over her than they show in the books! Thus, generalisations about the colour of typical individuals probably don't apply to her.
I have seen melanism in both small and Essex skippers, but the concentration of black along the veins suggests Essex to me in this case (though this effect can also be found in small skipper). I may be totally wrong and don't want to contradict Pete or anyone else.
The moral? I think it is only possible to be confident about individuals like this if you can get a glimpse of the underside of the antennae, which rarely lie (though the bright brown of small skipper can wear off in old specimens). Thus, I think it best to hang off and get a good view with close-focus binoculars or monocular and identify the species before going in for that perfect photograph!
Here is a pair of 'typical' small skippers. There is no doubt about the identity, as the male sex brand is definitive (and I saw it better than it shows here). The female is above - notice how totally different she looks from the atypical female in this post! She's bright orange all over, and the antennae are also light above.
Guy
edit: Sorry - I didn't notice the bit about these being different individuals in different places and on different days. In my experience, that marginally increases the likelihood of their being Essex skippers, since I have found more melanism in this species. But that probably varies from locality to locality.