Hi, I suggest that as well that you review your CV and make sure that your cover letter emphasises that you have the right to work in the UK and that you are determined to carve out a career. Whatever the job is that you happen to be applying for, do some quick research online on career paths for that particular job and mention this information in your cover letter. This will let employers know that you are thinking long term. Even if the job isn’t one in which you want to stay long term, the employer won’t know that!
I thought it was interesting that you said that you have been working as an interpreter but that it is ‘only’ a freelance position. Are you sure that you are really selling the skills that you have to be able to take work such as this? Personally, I think that different language skills is a valuable one to have and I would suggest that you really emphasise this on your CV.
Good luck with your job hunting.