Morning Stu
The fact you have a wiper issue would point me away from the Cluster initially
My thoughts are Footwell Module it's in the left hand footwell (well it would be 😅) Run a scan it should show up any issues. The Footwell control module on the 4.6 caused all sorts of odd stuff radio that would randomly turn on/off odd light issues seat controls. BMW say you can't swap them it has to be new and set up by them (wrong of course) I changed mine for an upgraded unit second hand it took longer to remove the old unit and swap it than it did to re-program it cured everything and probably stuff I hadn't found 😅
Dave
P.S I wont let the E70 on Whats App or Face Book just in case 🤣