She's a chip off the old block. I've no doubt the DoE took speed limits as a suggestion.
It's hefty penalty. I wonder if she's had previous tickets? One of our UK posters will know if this is normal.
Article says that she's had a few in the last three years:
Magistrates imposed four points today for the equestrian's latest offence - and then imposed the mandatory six-month ban for exceeding 12 points, following three previous offences in February 2017, February 2018 and December 2018. These were for speeding, a fixed penalty offence and a traffic signal penalty.