Hamwich - first try line of sight. I use a pencil type torch in the teeth (Commando style but end on), but a head light might work.
If you can get a hand up, all well and good. If not, first check the diameter of your new pipes. It might be worth inserting a narrower bore pipe up inside the original as a guide, then pull off the original, and slide the new pipe over the guide pipe. I would secure with a band of double sided tape, my best friend. If there's any slackness in the fitting, you'll need to pad it out. If you need a sample of neoprene or leather,(enough to pad) give me a shout.


DaveW
'05 Red Roadster S1
'16 Yellow (Not the only) Narrow AR GDI Plus 4