TOKYO, Sunday - Former champions England laboured to a bonus-point win against lowly Tonga in their opening Rugby World Cup match on Sunday, while fellow contenders Ireland threw down the gauntlet with an impressive victory against Scotland.Eddie Jones’ side were left to rue a series of handling errors under the roof at the Sapporo Stadium and they only secured the vital bonus point for four tries with three minutes left on the clock, running out 35-3 winners.