Because of the nature of the orbit, we cannot predict thousands of years into the future for this object, but in anyone's lifetime now, there is no chance

We really would need a transponder to improve tracking enough to firmly establish that an impact would occur.

That is, we would still not know better than one-chance-in-five whether the impact would really occur or not.

Whether you could see it from the center of London is another matter.

However, to actually know what your seeing, a small telescope would be useful.

Yesterday, we had a great rain storm for about 15 to 30 minutes, which helped matters a lot. However, today the rain is drying up and there is no more expected any time soon.