I don't want to sound stroppy: but, back in post #4, I stated that I had suffered the exact same problem, and that the only long-term solution (still going strong) was to replace the whole wiper unit -- a view that seems to have been echoed by others: particularly s and b.
I know it seems somewhat illogical: but I too had gone through various efforts at repair and investigation (apart from replacing the stalks -- because that seemed too complicated, to my simple mind...); and nothing lasted long-term -- even cleaning the old motor (plus, of course, trying the usual clips and reinforced linkage replacements...).
It's therefore worth a try, at least, surely -- based on the experience (which is what I presume you were looking for...) of a seasoned Forum member...? Even if you start off by using a second-hand one (although, on something so essential, I went straight to new -- because you don't know if a used replacement suffers from the same defect...).
Fair play yes its defo worth a try the only thing that was putting me off is the motor on hers looks very new and when opened was spotless very little signs of wear , i will find a second hand one to try in 2 weeks when i am back from working away thanks very much will get back to yoi with results
