As a general rule, the Courts will punish high excess speeding offences with instant disqualifications. Also, any driver reaching 12 penalty points within 3 years would face a 6 month disqualification under the "totting up" procedure. The mandatory guideline is that under the "totting up" procedure, a 6 month disqualification should be imposed but when the licence is returned, the slate is wiped clean and the points removed.
Other offences, such as drink driving also carry mandatory disqualification periods. When a disqualification is imposed for a specific offence, such as drink driving, the period of disqualification will depend on the nature of the offence itself and the licence can be returned at the end of the disqualification period with any previous penalty points still valid. Alternatively, if the offence is particular severe, the Court can disqualify you and order that you take an extended test before your new licence is issued.