Does anyone know why my English/French coast might look like this and how to fix it??

 

Theres also a funny perfectly square piece of land right next to corfu as well which im sure isnt supposed to be there

 

Cheers

That seems to be an issue with Ultimate Terrain. Try to run the UTX configuration tool, that should fix it.

worked a treat, thank you OE-LAT

That seems to be an issue with Ultimate Terrain. Try to run the UTX configuration tool, that should fix it.

I know it's a matter of semantics, but I'd like to change the wording a little bit.

 

This is an issue where some other addon comes and changes the Terrain.cfg file. Since the file is changed and removes the entries that Ultimate Terrain requires to display it's properties correctly, you will see problems like shown in the picture. The first layer for Ultimate Terrain is an exclusionary layer that removes existing scenery items. Subsequent layers add back revised scenery items. If the Terrain.cfg file has been altered and the entries that UTX needs are missing, it can't give you better coastlines, roads, etc.

 

So Ultimate Terrain is not the cause, but it does end up being the effect.

 

Too bad other scenery projects can't play nicely with existing files!

Thanks for correcting me, I didn't intend to blame UTX for causing those issues at all, and I didn't really think about how my wording might be received. Anyways, the OP got it working properly again, and that's what is really important!