Guidance on dress is given in Army Dress Regulations, which are widely available. These allow regional commanders to authorise the wear of medals for specific parades on combat dress. No additional guidance is necessary.
It remains the Army's intention that parade uniform (number 1 or number 2 dress) be worn for most scheduled public events. Number 2 dress is available to the TA for specific parades, and remains the uniform for general wear on Remembrance day.