If finally worked it out.
You know that little screw at the bottom end of the wiper arm? Tiny little torx screw, the sort you can remove and easily forget where you put it down and then get into a panic cause you know you should put it back cause its probably going to be important somewhere down the line and anyway youre a completist and no matter how small and insignificant things are you know, in your heart of hearts, when something is not there and it will just niggle you even though nobody else would ever notice that things arent quite right, not quite up to standard you might say and . . . . . . .
WHERES THE FECKIN ENGINE?