You're lucky you can see the fittings to ask questions. All the fire hydrants in Britain are located under the pavement, accessed by lifting a cover plate. There is then a yellow marker sign at the side of the road to show locations.
The following link is aimed at kids, but it demonstrates the method quite effectively:
http://www.angliacampus.com/education/fire/junior/hydrant.htm (The firemen among you might find the pages about the
London Fire Brigade of interest.)
