How can shop car park ignore Highway Code?

I went to Watford by bus but suffered a medical emergency relating to my disability, so my partner came to pick me up in my car.

- By Jill Insley

We had arranged to meet in the Sainsbury's car park but, when he arrived, all of the spaces were full, so he pulled over on double yellow lines for 40 seconds to pick me up. The Highway Code says you can stop on double yellow lines to pick up passengers. I then received a penalty charge for £100.

Despite explaining the situation to the car park manager, CUP Enforcement, it refuses to budge.

I don't find the Highway Code particularly clear about double yellow lines, so I asked the Department for Transport for clarification.