What's its date? We can't calculate the end of the discount period without it.
As regards the contravention, I don't see that you have a defence based upon what's been posted.
Signs aren't required; you've not suggested that you've parked in this way for years without issue(IMO the basis of legitimate expectation, not what you might have observed momentarily on the day); and there's no footway parking bays wholly/partly on the footway in Foxlands Crescent.