Hello
From the way you dislocated in the Physiotherapy assessment it sounds as if you dislocated anteriorly and therefore have an anterior instability. This is classically the 'stop position', imagine you are trying to halt traffic! So your vulnerable position at present is arm taken to the side 90 degrees with your fingers pointed up to the ceiling. If you have multi-directional instability other positions may be vulnerable also. So basically I would avoid or take care with any of these 'stop positions'. This includes butterfly, freestyle, back crawl and to a degree breaststroke! Gentle breaststroke with a small range may be ok but the resistance from the water will put more strain on your joint. I may go more for the snorkelling type of swimming where your arms are by your side or hold a float across your chest and use your legs. You may be fine swimming but the risk of it dislocating is there and being abroad when that happens wouldn't be fun.
It sounds as if the consultant is suggesting general Wikipedia reference-linkrotator cuff strength exercises where you resist taking your hand towards your stomach and away from you with your upper arm and elbow at your side. Also the rowing machine should be fine.
Laura