Defrost the frozen vegetables by spreading them out on a dish or baking tray. Allow them to sit at room temperature for 10 - 15 minutes; they do not have to completely defrost. Do NOT run water over them.
Chop the seafood into small pieces, and place into a large bowl.
In the bowl with the seafood add the vegetables and the mayonnaise and mix to combine. If you like it a little creamier, feel free to add a little more mayonnaise.
Add the Dijon mustard and pepper, and stir to combine.
Refridgerate until ready to use.
We find that this salad is best enjoyed a few hours, after it's made. This gives the vegetables ample time to thaw out and for the flavours to combine nicely.