Ground surface access cover assemblies

A ground surface access cover assembly (14, Figure 1A), preferably a manhole cover, having a first cover member 16 and a second cover member (18, Figure 1A), each preferably substantially triangular. The first cover member 16 has a first reinforcement beam formation 26, which extends across a central region (22, Figure 1A) of the cover assembly (14, Figure 1A) and defines a recess 24. The second cover member (18, Figure 1A) includes a second reinforcement beam formation 28, which extends across the central region (22, Figure 1A) and in an assembled condition is at least partially receivable in the recess 24. The first reinforcement beam formation 26 may have a web part 46 and a pair of spaced flange parts 56,66 forming a C shape in cross section and defining the recess 24 and also may provide a pair of laterally projecting formations 32 which locate through locating holes 34 defined by the second reinforcement beam formation 28. There is also a method of providing access to an underground service.