Hosts make French side pay for yellow cardsSaints progress to tie against Bath or SaracensButter-fingered hosts Northampton held off ill-disciplined visitors Castres to win 49-41 on Friday night to reach the quarter-finals of the Champions Cup.The French side collected two yellow cards in three minutes in the first half and another with 10 minutes left but they were also undone by their poor tackling and covering in defence and by three missed conversions from six tries. When Northampton did not...