In East Anglia the airfields were so close together that it was sometimes difficult for large formations to assemble without getting lost. There was a similar problem with returning planes. (A friend once talked about having to go fetch one of his group's aircraft after the crew got lost for three days - each day landing at a different (wrong) field.
In the Pacific, there were rarely more than four groups on an island - and frequently only one group! If there was a four-engined formation overhead, chances were good that that was where you belonged...
Cheers,
Dana