Jon
The road should be fairly quiet on a Sunday morning, so I would be surprised if there was any significant queueing on the hill. Normal rules of the road apply, so mounting the pavement is a non-starter. Don't try to save a few seconds at the expense of making yourself vulnerable, and never underestimate car drivers' capacity to fail to spot cyclists, especially in a queueing situation. Last year there were a number of penalties handed out for trangressions at the traffic lights in Harewood, but they also made time adjustments to compensate those who had to stop at the lights.
If you do find yourself faced with stationary traffic, think carefully about what could happen if you overtake the cars. They certainly won't be expecting a bike to come flying past on either the inside or the outside. Although 'undertaking' is illegal, I generally think it is safer than overtaking when on a bike. This is mainly because if you overtake and the traffic then gets moving again, you will find yourself in the middle of the road and struggling to return safely to the kerb. You could also get hit by an overtaking car which won't expect you to be in the middle of the road. If you 'undertake', then do it slowly; drivers are even less likely to see you and one could pull in to the kerb, turn left into a driveway, open a car door on you etc.