Viltrox JY 610 N II

Short review
So I got this small cheap flash off Aliexpress.com. This was mainly because it is TTL and has some nice specs and is pretty compact.
First the good news:

1. It is pretty compact. It is a  good fit on the Nikon D3200.
2. It does TTL well in my experience.
3. It is well finished, quality of plastics etc is pretty decent.
4. I tried it on my Ricoh Gr, works on Manual mode. Great!!
5. Has a pretty useful slave mode.

Bad news:

1. The battery compartment is bad, my rechargeable cells were too snugly fitting, once in they wouldn't come out without some cajoling.
2. Will have to find a solution to this problem.

Discovery

After a few experiments,I have come to the conclusion that the external flashes I have are not triggered by the flash on a mobile phone camera unit when in slave mode.