no worries mate. the easiest thing to do is look on the net at same engines as you, i'm guessing the corsa you're getting'll be is gonna be a corsa C 00-06 reg? also just a idea is to take the 1.2 badge off the back but perhaps leave the corsa badge on. that's what i'd do anyway if it was mine lol
have a look on the net at company's who do exhausts for them and it should be a standard fit for them if that makes sense lol.
being honest tho corsa's are obviously quite common motors to mod so shouldn't be too hard.
one other thing i will say tho is don't get a universal fitting backbox tho coz A they sound shite and they need a shed load of welding to fit too. again. hope this helps mate. i'm not too clever tho with this so please forgive me if i'm a bit out with the info lol