A ban upon reaching 12 points (or more) is not automatic.
The court is obliged to impose a ban unless there are 'exceptional circumstances'. Such circumstances need to be really exceptional. For example, magistrates are specifically instructed that the likelihood (or certainty) of the offender losing his job is not a sufficient reason for not imposing a ban.
Normally, 'exceptional circumstances' have to directly affect someone other than the driver. For example, if the offender had to regularly take his seriously-ill child (who was unable to use public transport) to a specialist hospital hundreds of miles from his home, he might escape a ban.
There's no upper limit to the number of points where magistrates can use the 'exceptional circumstances' rule. For example, someone might have 11 points on their licence, all of which have nearly expired. He then gets stopped for a relatively minor speeding offence (usually 3 points) and the police find out that he was using his car for business purposes when he'd only got insurance for private use (usually 6 points). That would make 20 points but, when he explained about having to take his child to hospital, the court might still decide not to impose a ban.
Chris