 Complete the following phrase:  In 2009, Thurrock T-Birds made it to the promotion playoffs in Championship 2 South East but lost in the final. In 2011, they defeated Oakmeadians Ladies in the playoff to be promoted to Championship 1 South. The following season, Thurrock T-Birds were promoted into the Womens Premiership after defeating Championship 1 North champions, Camp Hill in the promotion playoff. In doing so, they became the first Essex based team to play at the top level of English rugby union. In 2013, they finished bottom of the Womens Premiership which meant they took part in the promotion-relegation playoff against Aylesford Bulls Ladies. They lost and were relegated to Championship 1 South for two years due to there being no promotion or relegation in the next season because of the next season preceding the 