Chop the celery into pieces and blanch. Chop the apple and mix with the blanched celery. Mix the mayonnaise with the vinegar and garden herbs and add to the apple-celery mixture.
Slice the chicken into fine strips, season with salt and pepper and grill in a grill pan.

Place a few tablespoons of the apple-celery mixture on a beetroot wrap. Then arrange a few pieces of chicken on top. Finish with walnuts and slices of radish. Roll the wrap up tightly and leave to firm in the fridge.

You can easily prepare the wrap in advance and take it with you in your lunch box, or cut it into slices to serve as an appetiser.