I was reported by a off duty officer but the section 59 has been sent to me by an on duty officer who is dealing with the report he received from the off duty officer. I think the police only need a report from a member of the public in order to be able to issue one of these section 59's, which i think is bang out of order as there is no way of disputing it from what i can see which makes it a far easier option than court for the police!
The bit about a police constable in uniform i think is referring to when they seize the vehicle from you if you commit a second offence within 12 months.