For 2020 it is a requirement of Solo Road Race machines to be fitted with Lever Guards as per the 2020 ACU Handbook.
The new Ruling can be found of Page 267 and is as follows;
14.12 CLUTCH AND BRAKE LEVERS
4: Brake Lever Guards must be fitted. They must be robust, suitable for purpose and properly fitted. Classic or Vintage machines racing exclusively in their own race or event are exempt.