In my opinion, no, that would be unrealistic. You're not going to be head-hunted or snapped up as soon as you set foot in the country I wouldn't have thought; similarly £24k is a reasonably high starting salary so I think your expectations may be a little unrealistic (unless you're only considering London, in which case perhaps). However, there's nothing to stop you applying for jobs before you get here, and there are graduate jobs which will pay you that amount so it's certainly possible.
I'm not sure if you'd be considered on an *exactly* equal footing to a British student, mainly due to the potential lack of knowledge of the recruiter, but if you put some context on your CV (e.g. "I got x grade - roughly equivalent to a British x") then that should help them out. And I can't see why it would be any less important to have good grades from a Swedish university than it would from a British one, but - as you've mentioned - there will be other factors considered too.
Please don't consider me an expert on any of this - I'm not a recruiter or anything like that - but if you're looking for an opinion that would be my answer based on my (obviously limited!) experience.