Children's Activities and Parties in Wimbledon and Merton. If you're looking for something different for childrens activities and parties then consider Fighting Fit in Wimbledon, Merton and across South West London and Surrey: Fighting Fit offer expert and fun Martial Arts and Personal Trainers sessions that are ideal for men, women and children of any age, size and ability. So the next time you're looking for childrens activities - or something different for childrens parties - then give Fighting Fit in Wimbledon a call on 020 8715 0463