It was at a stage where they had a number of investors and a number of staff. I was involved in the software engineering of one of the products as an independent contractor. I'm not sure if its relevant but I left the company around 2 months ago before I started the rival business.
There idea doesn't have anything patentable or copyright protectable that I'm aware. And it could be easily copied by anyone else.
So the fact that we have tried to make it work and look as different as possible but retaining the same idea would mean it's likely to fall outside of the copyright?