Eileen Douglas tack shops.
There are hundreds, I find new places all the time. I generally google the item im after then trawl the results.
Currently really rate GS equestrian/equine. Good prices and service and free returns
Kramer Equestrian. Order a catalogue and you’ll be in heaven sitting having a cuppa too, flicking through it. I buy lots from them (have done for years) and have always been delighted with everything I ordered (apart from a sport bra actually that was absolutely tiny).