GB/England have always made beating 'lesser' teams hard work. Why I don't know. However they are infinitely superior in every facet of the game than PNG. As I say they will make hard work of it but they will do it easily in the end.
Tonga are a much harder proposition but true to the British nature the more they look like the possible underdog the better they will play. I think they will be pumped to play Tonga purely because they will be written off in some quarters.
That said I don't really care how pedestrian England are until the final, just grind out the wins if they can. England only need one maybe two good games and they are word champions.
My team Ireland did great, how can you win two and not get through - gutted!