I am almost certain they are legal requirement. Ant trailer dealer should be able to sort you out with a couple of guards and brackets to suit your trailer.
Look on the Towsure Website - they have a fantastic range of extras, or just fabricate some from an old plastic waterbutt / barrel (like my father in law did)
A day of all things motorhome and campervan. The show is held both in the main indoor arena and across the grounds. Catering, hot drinks and food options are available. Easy access to the site and free parking included. Win one of five pairs of day tickets