Yup, I agree with GrandePunto PL. The bolts on the front flange look typically horribly corroded and will likely refuse to be undone so needing to be cut off and drilled out. This is not unusual, my boy's 2012 Punto 1.4 Easy had bolts so badly rusted they didn't even look like bolt heads. Unless you're really into doing your own stuff I'd just take it to an exhaust shop, it's not a difficult one to do compared to some and they should handle it easily and quickly. The back boxes usually rust out much quicker than the centre pipe so if it's (the back box) looking ropey I'd just do that at the same time then you'll have a complete new system from the Cat to the back. Get them to put new rubber mounts on too, It'll be a pity if a dodgy mount fails after a few months and the new exhaust drops down and gets damaged.
On a more cheerful note your sump, from what can be seen of it in the pictures, looks to be in good order. These steel sumps are well known for rusting out. Your's looks like there's a small amount of rust on it which, if you can be bothered, would respond well to being rubbed down and painted over with something like chassis black or an enamel paint - don't just underseal it as that won't stop it continuing to rust.
PS. If you go to a "Faster Fit" type organisation (and they are generally competent at doing exhausts) and they subsequently give you a long list of other stuff that needs doing "urgently" then do nothing until you get back on here with some pictures and ask for some advice. These places often make their money by "upselling" on the original job and you may find that their "urgent" recommendations are not actually all that urgent!
