Turns out the tie-rod nut had come off and the rod had come out of its mountings

So I need to replace the nut, had a look on minispares and they don't advertise a specific one, so does anyone know what size I need? A link would be really useful so I can order some tonight...
While on the subject, I am going to replace the bushes for these, am I right in thinking the lipped side goes towards the mount? I know to use the soft on inside and the hard one on the outside

Finally, should I use a flat or a cupped washer on the end? If it is the cupped, which way should it be on?
Thanks!