BA CityFlyer Embraer 190 G-LCYZ operating BA4450 Rotterdam – London City diverted to Birmingham this morning due to weather at London City. The aircraft then positioned Birmingham – London City as BA9751 in order to operate BA7303 London City – Milan Linate. The aircraft then operated BA7304 Milan Linate – London City, but stopped the climb at 5,000 ft due to a technical issue and returned to Milan Linate for a safe landing.