Yep you can go to the shop, order it, pay for it and get the discount and then go pick it up when it comes in. Ive just done that and it worked out for me because i ran out of room in the car anyway.
The (problem) with their system is you can order online and then "click and collect" but only to certain stores. My (2) local stores arent part of the list so i have to do the above.
Still its a reasonable reduction and they seem to have so many these days i would feel ripped off paying full price!
Nearest one is Plymouth at 42 miles according to the website. And that's in a straight line.
Next closest is Cardiff at 52 miles. I'm not that good a swimmer