I will resolve 'yes' if they vote to strike, and then actually end up striking. The strike could, for instance, be called off or postponed by the government engaging in new talks or offering restoration of previous salary levels. 

From British Medical Association (their union):

 of those eligible to vote in order to be considered to have support for industrial action.

An additional requirement exists when the majority of voters are engaged in the provision of 'important public services'. In these circumstances, the Trade Union Act 2016 requires that at least 

40% of those entitled to vote must vote in favour of industrial action. 

The BMA is currently assuming this to apply, judging their recent statements. 

I'll resolve this if they strike, or near/at the end of 2023 if it's  very clear that they have no time remaining in which to ballot/strike. 