I'll do the second one first. The projections are called halteres. They are mutated wings, primitive insects having 4 wings, but true flies only have two wings. The second pair are modified into what are essentially gyroscopic stabilisers, which beat up and down as the insect flies, giving it stability and enormous sensory feedback about its flight. This is why flies are superbly agile fliers, compared to things like beetles or butterflies. Halteres are unique to flies.
Now, that other insect is also a true fly, and assuming that it is a UK insect, a cranefly, but not of the genus Tipula which we normally associate with craneflies. Actually, having looked in my book for some assistance, I think it is Ptychoptera contaminata, or at least one of the Ptychopteridae, which are not true craneflies, but are closely related. I'm not expert in the group, so could not be confident to species. In fact I've never seen one of those before, and it is a lovely looking creature. Thanks for showing it.
