Statute of limitations
I can understand the logic behind having a limit, for less serious charges - a long delay could make it difficult to mount an effective defence against charges, making it unfair - but I don't think that timer should tick while the suspect's aware of the charges and "on the run", as in this case. It's not as if he's unaware of the charges, or unable to defend himself in court, so why should the limit apply?
The idea it's all a plot to get him to the US (because of course Sweden is closer to the US than the UK is?!) doesn't hold much water - so why not go to Sweden and beat the charges, if they're so baseless? Going on the run just makes him look guilty.