Umm... Velorution?

That's just shitty behaviour from the owner. It's also in breach of trading laws.

I could understand a refusal to sell at the marked price if it was accidentally wildly out and would never hold a small independant trader to that. However, if the gloves were bought to be sold at a price then it suggests that you aren't costing them anything to buy them at that price.

I've never been to VR, and living outside of London doesn't make it much of an option. But I can now say that I would be inclined to actively avoid them. There are a number of other independant cycle shops that demonstrate much more business sense and a far better approach to customer service.

What trading laws are those?

There is no law stating that you have to sell something at the marked price.