Think I might've fixed it! Just went to start it up and it didn't want to know... moved the steering left/right a few times and tried again, nothing... tried killswitch a few times, still nothing... ignition off/on a few times and it fired up straight away 
Loads of contact cleaner down the keyhole and turned the key a few times to get it all round the switch so hopefully it won't happen again, time will tell I guess. Will also find out of this was related to the hesitation, but I'm not too hopeful there to be honest.
Got rid of the chirping noise too, loosened off the chain by half a turn and gave it a clean/lube.
I also learnt to move the chain round by turning the wheel, not the chain, because if you move it round when your thumb is nearer the sprocket than you thought it gets squished and bloody hurts :'(
Loads of contact cleaner down the keyhole and turned the key a few times to get it all round the switch so hopefully it won't happen again, time will tell I guess. Will also find out of this was related to the hesitation, but I'm not too hopeful there to be honest.Got rid of the chirping noise too, loosened off the chain by half a turn and gave it a clean/lube.
I also learnt to move the chain round by turning the wheel, not the chain, because if you move it round when your thumb is nearer the sprocket than you thought it gets squished and bloody hurts :'(