Hi, regarding RCP chassis parts i had a half chassis fitted to my 1996 110 csw in jan 2017, one of the first they made, they actually delivered it to my engineer in Wiltshire. It has various parts to improve it from original. So far so good December 2019. Hope this may help somebody.
When replacing seal and flange its VERY important to undo axle breather from casing and clear all muck from both angle piece and pipe ever so easy to do and fixed my leak before i changed seal any way as it was 20years old. Mine was totally blocked with rusty oily muck.see brittanica restoration on u tube.