The grounding is voluntary, so far. Very responsible move from Bond. The grounding is mandatory if dictated by the Agency (EASA)
The way ahead is that after the report of Bond to Eurocopter and the UK CAA on the finding (mandatory) Eurocopter will investigate and come out shortly with a document to all operators: if Eucocopter has reason to belive that the problem can be present on other helicopter (and not only of that helicopter s/n) will come out with an inspection program/temporary repair (normally through a Service Bulletin or an Alert Service Bulleting, depending on severity). In case of Alert Service Bulletin is quite normal that EASA will follow with an Airworthiness Directive (AD) shortly after.
Depending on hazard of the cracks the inspection on other aircraft can be within a certain period (as on blades i would say Flight Hours) or, in worst cases, before next flight. A temorary repair can be proposed by the manufacturer, or a subsequent inspection schedule, if possible, to permit the helicopter flying.
Eurocopter at the same time, or later (in a revision to the Bulletin), will propose a terminating action to solve the problem.