Welcome. Your first starting point should be to contact Morrisons, explaining that the driver was a genuine customer. Morrisons anecdotally have a decent track record for intervening in these matters, and even have a dedicated form on their website that can be completed:
Got a question? Ask away. Your Morrisons Help Hub is here to answer any questions. you may have. Select your help topic or search for your questions.
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If you don't have any luck with them, then ECP charges can still be beaten, but it can be a somewhat protracted process - basically you appeal first to ECP and then to POPLA. If both of those are unsuccessful, you then wait for them to initiate court proceedings. ECP usually use DCB Legal who, if you defend the case, nearly always discontinue before the hearing.
It does state that other signs are present.
There certainly were as of March of this year:
Here for example