Menzies Aviation are hiring for ticket desk agents at London City Airport, I remember seeing an advert recently placed on
www.aviationjobsearch.com, but I can't remember any of the T & Cs or what relevant experience is required.
Remember there are always plenty of positions at other London airports if commuting is possible. Plenty of airlines & handling agents at LHR (and some at LGW & STN) hiring also.