Police are urgently appealing for witnesses.
The two, who were on a golfing holiday, have been left with a broken jaw and another with a broken nose after the violent assault.
It happened on Market Street at some point between 11pm on Friday 6 July and 12.15am on Saturday 7 July.
Following a minor altercation at a bar, two holiday makers were followed and violently attacked by a group of unknown men.
The first victim, a 54-year-old grandfather of four, was punched to the face causing a broken nose. His son, a 28-year-old man, was attacked causing a broken jaw for which he received hospital treatment.
Police believe that there were a number of witnesses present and would like to speak to anyone who may have information that can help with enquiries.
Anyone who was present or could offer further information about this incident is asked to contact the police on 101 or 101@DC.police.uk quoting crime reference CR/060583/18.
You can also give information anonymously via Crimestoppers on 0800 555 1112.
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