I just assumed I could not pay as parking was suspended
I thnk in that case, unless someone comes up with a technical argument re the PCN, I would grab the discount.
I haven't checked Manchester's Traffic Order but yet to see a clause on any that not only allows them to suspend but cancels all other restrictions...though the latter could possibly be argued against the suspension effectively meaning that there is no parking area so no restrictions can apply.
Why they didn't enforce against the suspension is anyone's guess?