Fitted the door seal yesterday, not too difficult to do
The seal is actually both the inner and outer seal fixed together.
You need to remove the inner door furniture, then you will see (on mine at least) a foam strip, on the back of this foam strip is a plastic tube which slots into a series of "clips". this bar slides out, easiest way. The inner seal then is easily removed.
The outer part is fixed in a similar way. The plastic "tube" is on the inside of the door skin, its a little more difficult to reach, but this slides out as well.
To fit the seal (I had help which made this possible) we gently folded the inner seal back and fitted the outer seal, the plastic pipe we slid back through the clips.
When this was fixed, the inner seal was fitted and the plastic tube was slid back.
Hope this helps