'It's a very difficult time,' says son of missing parentspublished at 19:02 BST
Alex Forster
Reporting from south London

Prajval Haldia says he can remember dropping his parents Pavan and Kavitha off at the airport for their trip to Kathmandu, spending a few days sightseeing before moving on to Mount Kailash.
He is speaking from the south London Sanatan Mandir temple, where 16 people from the community have been missing since Wednesday.
The group have been meeting daily since the disaster struck, with some expressing a desire to travel to join the search and rescue effort.
Prajval tells the BBC: "Everyone here is in the same position and that's really helping."
The son says he is trying to stay positive, adding "no news is good news", and that he has been in contact with the Foreign Office and his local MP.
"Obviously it's a very difficult time. There's ups and downs when you think about certain things, but we're just hoping and really praying that everything's ok and they are going to be back soon," he says.























