Can you clarify something? Given a valid UK App Store link to your app, can you click on that and see your app in the store?
If so, then your app is in the store. If not, then you'll have to contact Apple Developer support and ask what's going on with it.
But if your app is in the store and you can't find it via search, that's a whole different question. The bottom line is that you can't depend on Apple for app discovery. Maybe you could have better keywords, description, or app name - I don't know. But search is a proprietary black box. If you can find your app via search, Apple isn't going to tell you why. You'll either have to make changes via blind guesses or promote your app via other channels.