From the ruling statement:
“The alleged offence set out in the Application for Summons is that the Claimant “repeatedly made and endorsed false and misleading statements concerning the cost of the United Kingdom’s membership of the European Union”. It appears that if the Claimant had said/endorsed a figure of £350m per week gross, or £250m per week net, there would have been no complaint.”
https://www.judiciary.uk/wp-content/uploads/2019/07/2019ewhc... (search in doc for "350" to find the juicy bits)