Magistrates’ sentencing guidelines suggest a fine of a week’s net income (reduced by a third for a guilty plea), plus either 4 to 6 points or a ban of up to 28 days. You will also have to pay around £80 in costs and a £15 Victim Surcharge.
I must say it is unusual for an immediate ban to be imposed below 100mph unless there are other aggravating features.
As far as the reasons for avoiding a ban go, strictly speaking woolfgang is correct in that it is the circumstances of the offence itself which mitigate the matter, not the effect the ban will have on the offender. Magistrates only consider such “exceptional hardship” when a ban under the “totting up” procedure is due. However, magistrates will take into account the effect that a ban will have whenever considering disqualification and it may tip the balance if they are on the cusp of imposing a ban.