The Lemon Fool

Does anyone have any recommendations for a replacement unvented cylinder please? (Economy 7, no gas). The old Ariston is leaking at both immersion heaters and a couple of other places. A ballpark installation cost (mid-Essex) would be good to pass on (fortunately, I am asking for a friend so I am not the one footing the bill!).

Cheers,

Julian F. G. W.