The son in law has correspond with Groupnexus, they have emailed back:
We can confirm that as long as the duration paid for covers the duration parked on the correct date, this will be sufficient.
Should you receive a parking charge, please appeal accordingly as we can only deal with active charges.
Your faithfully
Group Nexus
The son in law has previously made payment on the date of offence and forwarded me a receipt, lets see what happens.
Unfortunately I have suffered a brain injury and occasionally I get confused and often say the wrong thing.