I seem to have reached a crossroads. I'm not stressed by it, don't lack the motivation to do it (I want to get this over and done with), I know what I want to write but just can't get it down on paper. Any advice, tips etc?

Take the rest of the night off and come back to it tomorrow with fresh determination! You can do it Delta!!!:p

(positive self talk)

Maybe just write without filtering any of the ideas. If you know what you want to say I would get it down on paper (or screen) asap and then edit and tidy it up afterwards. The important thing is to keep hold of the ideas and jist of whatever points you are trying to make. Alternatively if you're working from home or in a private office, speak your thoughts out loud into a recorder or phone and then transcribe and edit afterwards. Might help the writing juices flow :-)

Thanks Ady, that's good advice. I've made bullet points and will expand on them but will take the rest of the night off.