We have worked hard not to have any middle-men that mark up rates in our liquidity provision, and are quite certain that our rates are fair and extremely competitive.
I do think that the takeaway from your comment is that we could build out a part of our page that allows a customer to dig deeper to validate this themselves. We understand the sentiment as there is still a lot of mistrust given the opaque nature of the market, and we need customers to believe that we are truly 3 GBP to succeed.
Our core thesis in building this product is that we will win with a fixed fee on larger transactions, given the variable fee nature of the current industry incumbents(either transparently disclosed, or embedded in the FX spread).