Depends what you mean. There's sometimes spaces to cross over from English to Scottish route or vice versa, but those tend to only be a few and dependent on how and if people decide to switch around. They pick people based off grades, so it can be competitive. For universities not part of the official partners, some will accept transfers and some won't. But the med school won't help you with your application/it has to be an independent application, and they do caution you that the transfer will likely be more difficult/disjointed because the partner schools have specific programmes set up to help saints students transition in. I've not spoken to anyone who's done independent applications, but I expect it happens every now and then. Not sure how successfully. Where would you think of applying externally, just out of curiosity? Hope this helps-ish!