If we leave Mile End at 09:00 and are progressive, without being silly, we should easily be there by 13:00 or not long after.
Worst case scenario, somewhere between 13:00 and 14:00.
The 13:51 from Cambridge arrives in Lpoo St at 15:15.
2 trains ph, 32 and 51 past the hour.
I am expecting to be on an earlier train.
Does that work for you?