A lot depends on the lighting. Yes, they are two different colours, and they do make a difference.

For starters, I would try to match the black of the jacket locally in both colour and texture.

Then have a waistcoat (vest) made up. It would probably be somewhat cheaper than going back overseas to rectify it.

Finally, when the exchequer will stand it, get a dark blue to match the vest, and a balmoral in the same colour. (You might want to get a Crail with bone buttons, or some other variant that is somewhat less formal than the Argyle with silver buttons. (Ask for a swatch, and have it checked in bright light.)