Slice the radishes thinly and pack into a mason jar. (You can use a Pyrex bowl if you prefer).
Add the mustard seeds, celery seeds and red pepper flakes.
Heat the water, vinegar, sugar and salt to a boil then carefully pour over the radishes making sure you cover them completely. Seal the jars or cover with plastic wrap and let cool. (These will keep for a month or more in the refrigerator)
Toast the sliced baguette.
Spread with goat cheese, top with the radishes and sprinkle with some crispy bacon