I would honestly upgrade to breakaway brakes, I know there is ADR exemptions on trailers made or imported before that year but there is another issue where your insurance may be void as it may be considered unsafe or overloaded.
Whilst your looking at it check the rims and tyres for their ratings as they possibly have been changed in that period to a lower rating, if so you would have to still go down the path of changing them over to meet the ATM rating.