(Reuters) – London-focused flexible office-space provider Workspace Group said on Thursday that Graham Clemett, its chief executive of five years, would step down this year once his successor gets appointed. Clemett, 63, leaves at a time when flexible space operators such as Workspace have outperformed the traditional landlords on the operational front in the UK, as tenants opt for short-term leases and reassess their strategies periodically amid lingering broader economic worries. A British national, Clemett has been with Workspace for 16 years, initially as its chief financial officer and th…