Pro-Direct are an online retailer who have "stores" for tennis, football, rugby, running and cricket. I don't believe they have a physical store.
JJB was owned by Wigan FC/RFC chairman Dave Whelan and the chain faced financial issues a few years back - some stores and the gym chain were renamed DW Sports (in his name) and the other non performing stores went to the wall. I assume even tough JJB are in admin/sold to Sports direct the DW stores/gyms will still operate.
JD Sports have never been a sports shop - more a clothes retailer!
Sports Direct is owned by Mike Ashley who also has a share in the UK Dunlop/Slazenger business, hence the stores started as an outlet for their products and grew to include other brands. Still essentially a clothes retailer they now sell cheap racquets and golf clubs as well as other bits of random sports equipment!
Do you expect me to run forward and get it in one bounce when I am hitting? - Sureshs 2014