As it says in the guide, details of dates and times can be critical to a robust defence, and witholding them from us means you eliminate possible avenues.
Personally, I would “appeal” by stating that you did not “Exceed the allowed limit” as claimed, and their notice does not state anything to support their claim because it does not state any “period of parking”. Further, the absence of any “period of parking” means that PoFA 2012 can not be used to transfer liability from the driver - whom you will not be identifying - to yourself as registered keeper.
You seem to be the victim of a rogue warden here.
They may well ignore your appeal, stating that “after careful consideration” the notice was correctly issued, or some similar rubbish, which means you will have to construct a longer appeal to POPLA in which you spell out the deficiencies.