Went back over previous things I had to done to see if I could figure out my missfire/eml issue. So on removing the tank inspection plate I found a wet patch!
So i removed the sender to get a good look. It seems that running veg had caused a build up of gunk on the top of the tank that mates with the bottom of the sender.
Scrapped and cleaned the top best I could with a wallpaper scrappe, cleaned the all the old veg oil off the large rubber o-ring and bottom of sender unit.
Cleaned that cup that sits on the bottom of the pick up pipes which was filled with dirt and residue.
Had a look around the tank as it was nearly empty. No debris floating about but stained the same as i had seen in one of Banshees threads. So put it all back together with the hope that it would help.
This morning was cold so took longer to fire up, rough for a few second but went straight to normal idle. When cold there was no issues with revs of the eml coming on. So seems it was a combination of dragging in air through the tank seal and blockages in the pickup. Shes running lovely now so well pleased!