Airbus aircraft A318/A319/A320/A321 with a MTOW<68T are compatible with 30m wide runways as per ICAO. However, due to Airbus practices to certify the aircraft, it is not possible to operate these aircraft on runway width below 45m without additional considerations
Basically any airline operating a "W" pattern through Southampton would need to ensure that the plane and the crew are certified as above. This means either all of the planes and crew need training/ certifying or only the few that operate to Southampton and risk disruption if there is a crew or plane change due to operational reasons.
Also, Boeing article showing decreased cross wind limits and need to increase VMCG leading to higher V1 and therefor more risk of a high speed abandon and more time for engine to fail on take off.
http://www.smartcockpit.com/docs/Nar...Operations.pdf
not being negative , just bringing facts from many years flying both airbus and Boeing