Well, they shouldn't. Their blue badge doesn't entitle them to park in - "Parking places reserved for specific users such as resident’s bays or loading bays. (However you may wish to check whether a particular local authority has chosen to exempt Blue Badge" so you (or the vans legitimately delivering) would be entitled to report anyone who does that, just as you are entitled to report anyone abusing a badge or a disabled parking space. It is not the fault of the blue badge scheme itself, or the mostly responsible holders of one.
See what are the rights and responsibilities of blue badge holders. www.gov.uk/.../uploads/system/uploads/.../blue-badge-rights-responsibilities.PDF
Bear in mind, everyone, before you criticise badge holders too readily, that the purpose of the badge is to even out some of the difficulties faced by those who are unable to get around without pain or exhaustion, or other disabitiies. If you have had temporary mobility problems, you will know how unpleasant it is. Multiply that to cover ALL mobility, 24/7.
Inevitably, some people have less disability than others, and a few are swinging the lead, but you cannot know exactly what their position is.
Retiring and living frugally in money from downsizing after years of stress



