As other posters say above. There is absolutely no point in asking for a BA roster. Where there might be limited value in getting to see typical rosters if ones starts working for an airline, at BA there isn't any value in it what so ever.
Pilots in BA have so much roster control (long/short tours, day trips, weekends at work/off, long sectors, short sectors, typical destinations, avoid destinations, mid-haul, days off in big blocks or evenly spread over the month, etc) that what might be ones ideal roster is another ones nightmare. Therefor rosters are a very personal thing and just because a pilot gets a few mid haul trips, another might have mainly day trips because of her/his preferences. This isn't going to change with JSS.