...it would come with a guarantee of at least 10000 hours, which wouldn't get us even to the EU referendum, let alone Jeremy becoming PM
10,000 hours   = 416.67 days.
One year (2016)= 365    days
Remainder      = 51    days.
That would get us to 15 Dec 2016
In June this year David Cameron said that we'd have a referendum "within a year". so I think 10,000 hours may be more than enough.
Any way, it is not possible to state that it will not be enough, with any certainty.

As to Jeremy Corbyn becoming PM, we now have 5 year parliaments, and even if that wasn't the case, I don't believe that the loss of the sun as a source of heat would be great enough to cause Hell to freeze over!