Is there a way to check it? I have an application URL, which I don't want to be opened expect if the user have a uk appstore. unfortunately, this application is available in many country, so when I put 'gb' on the link, it be redirected to the local region of the user.
You could use the in-app purchase Store Kit to achieve this.
Request the product list using SKProductsRequest then check the returned SKProduct's priceLocale to see if the user's AppStore is the UK one.