Welcome to the forum.

I will have a look at our locker seal when next down at the boat (2007 model) but I am sure that it is the same as yours and must admit to not having problems with it.

In a previous life I used to manufacture items for a number of marine uses and once made a number of flushfit GRP lockers and locker lids for Canal boats. It became obvious that the rainwater seal would quickly become damaged so having considered the options I moved the seal so it was fixed to the lid which provided a much better solution. This maybe an option in your instance.

These guys may also be able to provide some advice – http://www.sealsdirect.co.uk

Kind regards