I may have commented on this on another thread and my experience in this relates to Spanish but the same certainly applies.
The Crown Office and Procurator Fiscal in Edinburgh withheld crucial documents in my own case for over a year which originated in Madrid. They claimed it was an oversight yet my Counsel asked for them on several occasions. Judges in the UK tend to believe and side with Crown Counsel - they never lie you see!
When my lawyer eventually received them the day before a crucial hearing the Sheriff in Edinburgh refused to accept them as they had not been translated. That aside, we eventually received a translation from the Crown some time later. Coincidentally, it just so happened that my lawyer sent a batch of documents to be translated and amongst them was this same document which when it came back had a completely different meaning and that was caused by a single word!
My experience with Spanish is that with the best will in the world it cannot be translated into English and retain the exact same meaning as the original. Consequently, legal documents are a complete minefield!