Make your own mustard and have it taste to your liking. You can make it sweet, hot or perhaps ad herbs like for instance wild garlic. Frida used mead for her mustard:
6 tablespoons mustard seeds
2 tablespoons whey (or wine/apple vinegar)
1-2 tablespoons mead
½ teaspoon salt
1 tablespoon honey
You can start by roasting the mustard seeds before crushing them, and you will get a smoother rounded taste. If you prefer a hot mustard, use the seeds as they are.
Put the mustard seeds in a mortar and start crushing them. Ad the rest of the ingredients and keep crushing and mixing. It's up to you just how coarse you like your mustard. To achieve a fine mustard, anyone but the Viking lady could use a blender for the job. Season to taste. Perhaps you want to ad more mead.