Any ideas on these?

Cap: dark brown, smooth, sometimes paler near cap edge, overhangs gills, to 3cm, but may grow bigger
Gills: distant, cream (grey?)
Stipe: white, fibrous, to 4cm
Susbtrate: soil in mixed woodlands (birch, oak), growing in clumps, fused together, of a dozen or more individuals
Smell: present but not distinctive