I suspect it could all come down to when you claim.
With you and Heliguy both being in the UK I'd say there is less uncertainty with 'shipping', plus I have found that I can talk to the Heliguy people over the phone, which seems such a novelty!!
Against that is the fact they can only repair IF they have the parts available, and I doubt anyone would expect that to happen before, oh, pick a month, let's say June 2017.
You do understand Heliguy will only sell their insurance to their Customers (those who have bought the drone through them)? If you have already ordered from China, especially if it's too late to cancel, you choice is Care Refresh or nothing.
Delivery of the drones (never mind parts) seems especially uncertain at the moment, both from China to agents like Heliguy and from China to those who have ordered direct with DJI.
So, the answer is part determined by your drone order, and any gamble you make on dealing with Heliguy or DJI direct.
Hope this helps.