Mix the marinade ingredients together in a large bowl. Add the chicken, mix well, then set it aside to marinate for 30 minutes.
Meanwhile, place the rice in a saucepan with 500 ml of water and a pinch of salt. Cover, bring to the boil then reduce the heat and simmer, covered, for 20 minutes, or until tender. Transfer the rice to a large plate and leave it to cool until tepid, stirring occasionally with a fork.
Heat a tawa or a nonstick frying pan over medium heat. Remove the chicken from the marinade, season and cook for 10-12 minutes, turning regularly, until it is browned and the juices run clear when pierced with a knife. Transfer the chicken to a plate to rest for 5 minutes, then dice it.
In a large bowl, mix together the cooled rice, chicken, cucumber, mushrooms, radishes and herbs. Stir in the mayonnaise, lemon juice and Maggi and Worcestershire sauce. Season to taste and serve.