More photos on Flickr,  a Youtube clip  , and the stall-holders were: 

Affinity Water                                        
Anytime Fitness                                    
BeeZee Bodies                                      
Carers in Herts                                     
CHILD UK                                               
Children’s Sickle Cell Service              
Churches in WGC Peace Tent             
Cruse Bereavement Care Hertfordshire
CSP (Community Safety Partnership)
East & North Herts NHS CCG              
East & North Herts NHS Trust             
Finesse Leisure                                      
Friends of Welwyn Care Homes         
Gosling Sports Park                              
Health & Vitality                                    
Healthwatch Hertfordshire                 
Herbalife Wellness                                
Hertfordshire Chiropractic Clinic        
Hertfordshire Health Walks                
Herts Vision Loss                                  
HPFT Wellbeing Service                       
I Liq Chuan                                                       E:
John & Kelnack Pharmacy                   
Mears Home Improvement              
Mind in Mid Herts                               
Public Health & Protection                
Riverford Organic Farmers                
SFO Sports Centre                               
WGC Library
Welwyn Hatfield Sport and Physical Activity Alliance
Wise Choice Solutions                         
YMCA/Macmillan Move More Herts
Youth Connexions