I will look into the "exceptional hardship" but I'm not confident it will help.
No it won’t because it is not available to you.
Whilst you can explain the difficulties a ban would present, formal “Exceptional Hardship” arguments can only be made when the driver faces a “totting up” ban (12 points within 3 years). Since six points is the maximum number that can be imposed you are not in that position.
The sentencing guidelines for 61 in a 30mph limit suggest either a ban of up to 56 days or six points. That band of seriousness begins at 51mph, so you are well into ban territory.
Too late now, but your better option would have been to have chosen not to attend court and have the case heard (in the first instance) under the “Single Justice” (SJ) procedure. You cannot attend an SJ hearing but the single magistrate dealing with your case would not have disqualified you in your absence. If a ban (rather than six points) was to be considered your case would have been listed in the normal Magistrates’’ Court and you would be asked to attend. That is the situation you are now in but you have lost the “first bite of the cherry” where the SJ may have dealt with you by way of six points.
None of this explains why you have been invited to a “case management” hearing as, from what you say, there is no need for one. You should simply be attending for sentencing. It is my guess that you have simply been sent the wrong template letter.