From what I have seen, this is I think a fairly long running issue, but, (and I could be wrong), I think it has not blocked navigation completely. I think that when an engineer has been present they can probably override things and get boats through. However i think I saw that the engineers have to travel a long way, (somewhere like Nottingham possibly, but that's just a stab at what I think I saw).
if you are coming from Teddington, I suspect it will be back in action before then.
That assumes it doesn't break again, of course!
Edited to add:
Looking at the stoppage notice it was declared fixed, with the canal open, yesterday 9/6/23......
.... only to be declared broken again the same day.
So, presumably, some boats made ot through as recently as yesterday.....