Although there are a couple of posts regarding this issue on the forum I couldn't find any specific answer. So decided to try my luck.

I'm an LLB student (recently finished a second year) and decided to do an LLM in the US. Because my desire is to practice law in America I would need to obtain JD at some top t-14 law school, since the firms have a strong preference for a JD applicant rather than Masters one.

Although I do know that some schools allow to transfer from an LLM to JD, I was wondering whether it is possible to do an LLM at one law school and afterwards a JD at another one?

Or perhaps you would advise to do Masters here in the UK and then apply for a JD in America?

If you do an LLM in UK, you will not be able to save one year.

As far as I know, Chicago allows LLMs to transfer to the JD program regardless of where they pursued the LLM. The only advantage for Chicago LLMs is that they do not have to take the LSAT as well as pay the application fee.