Got to say rock boot shopping in Scotland isn't fun. Best bet are the shops attached to the walls, so Ratho, TCA or GCC. Means you don't waste a day visiting out of the way shops that don't stock what you are looking for. Or take a trip to the lakes.
Depending on what you need, GCC stock 5.10 Dragons, La Sportiva Miuras (velcro and laces), Evolv Shaman, Evolv Geshido (Velcros), Evolv Defy, Evolv Bandits and few more. As far as I remember, they offer 20% (or maybe 10%?) off for "Climb Unlimited" (27 pounds/month pass) members and students.
They do not allow to climb on the walls, though they have few footholds to test them in the shop.
My first pair of shoes was bought in Go Outdoors, but now I've got Shamans from GCC and I feel like I didn't do a mistake buying shoes at GCC. They know what do they have and they are helpful.