It would help to find the ends, though you can winkle it out with a small blunt screwdriver if you're careful. Try not to stretch it. The ends will almost certainly be hidden under one of the awning brackets. It pulls out - and goes back in - quite easily, but if you feel the need to replace it with nice new stuff, Jandi sell it at 50p a metre.
The stuff they sell is the original infill strip as fitted at the factory. Herzim does the same job, but isn't quite the same profile and may not be quite as easy to put in. The OEM stuff zips in really quickly once you get the knack, and there's no real need to warm it up first.
It's a doddle to do, and smartens up the outside no end.
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