If you have the stock Y-Pipe then I would upgrade . You could get something like the japspeed one which is quite popular (£180 ish) or a motodyne one (£400 Ish (I think)).
You can just get to it if you remove half the bumper on that side........ but bumper off is easiest. I am a dab hand at this now. should only take 10-15 minutes.
Give me a shout if your stuck