Not sure what Doug is referring to but this is picture of mine which look very similar to your new ones Rog.
![[Linked Image]](https://i.imgur.com/hgZEBUN.jpg)
It's the outer lip that has split at the bottom.
Richard, I noticed when new my seals were applying a lot of twist to the lip as the sidescreen frame closed & opened over it, I put a steel ruler against it and carefully trimmed a tiny sliver off with a scalpel, which solved mine, plus I lube them occasionally with a bit of clear Autoglym tyre dressing on the 'fin'