CCTV pictures have also been released of Samuel Guidera visiting a corner shop before he was stabbed.
After leaving the store, he walked towards the bus stop on Newlands Park, where he was attacked.
More top news
The 34-year-old victim was left with a huge gash across her nose and face. Police need to find a man seen on CCTV.
The girl was travelling on a train from London Liverpool Street to Romford in Essex after going to see the poppies at the Tower Of London.
Wealthy businessman Ivan Massow wants to succeed Boris Johnson at City Hall in 2016.