We are dubious that the sentencing judge is going to hand you a sentence that is 5 - 10 years and allow you to leave for the UK shortly thereafter. Typically what happens is you are taken into custody to serve the time imposed and then upon completion of 85% of that sentence you are extradited. Since we are not lawyers answering these questions this might be something that we've never come across or heard about. If they allow your release it would be a first from our perspective.
https://www.inmateaid.com/ask-the-inmate/can-i-avoid-serving-a-long-sentence-in-the-us-by-being-transferred-to-the#answer
Accepted Answer Date Created: February 18,2016