i emailed love film to ask if their lovefilm instant service provides this and they say they are working on it but not yet - below is email
Thank you for your email regarding subtitles on our LOVEFiLM Instant service.
Providing both closed captions and subtitles is something that we would very much like to be able to offer, for as many of the titles in our streaming service as possible. Whilst we are actively working on this, we don’t yet have a timeline confirmed for availability. As this progresses, we will ensure that we keep our customers fully updated about this ongoing development.
However, I am happy to confirm that the majority of our DVD and Blu-ray titles do provide an option for subtitles, which can be confirmed via each individual film or TV show’s product page on our website. So it is still possible to enjoy access to almost all of our 70,000+ available titles and still have access to subtitles.
I hope you find this information useful and continue to enjoy the LOVEFiLM Service.