I have absolutely no idea about this type of thing, but does anyone know anything about designing your own custom running shirt, ie for a charity event? I know companies that do discounts for bulk orders, but they still seem expensive. I assume all offer discounts for bulk orders? Are there any local companies? I assume all the ones I've found so far are some of the most expensive that Google can muster.
https://www.gdzsport.com/ Local and good quality. I’ve purchased several football kits from Simon, top bloke.
I know nothing about this sort of thing, but Rhino sports who supply the Elite Ice Hockey League are based a 10 minute walk from my house in Sheffield. Their website suggests they do running shirts and have a 10 day turnaround.