Technical Sill plastic covers

[farmer.palmer]

I am being dim and I cannot work out how to remove the plastic sill covers (trim) on my Mk1 SX. I have removed the three screws on the outside. Then pulled the internal carpet back and taken out the small screews hidden inside the sill, but the bloody things still won't budge. What have I missed? I have done a search but I cannot find any direct mention of this which makes me think its something obvious.

Thanks

 

[a73uk]

This is the eper picture, there seems to be a riveted (?) bracket at the front of the sill (11 & 14), but theres an odd number of screws which is a bit confusing.

There is a possibility they may have been `glued` on with silicone sealer too.