If you’re using translation services in UK, it’s important that you make sure your translator is qualified. In the same way that non-native English speakers can sometimes use the wrong grammar or use expressions wrong, a translator who is only slightly skilled at the language you’re translating to can mess up the translation. A grammatically incorrect and inaccurate translation can come across as extremely unprofessional so it is always best to make sure that your translator is proficient in both the language of the source material and the language which it has to be translated to.
If you’re translating to French for example, you’ll want to make sure that your translator is skilled at French. Ask to see previous work as well as feedback on their work. Also ask for their qualifications and any other proof that they might have of their skills. It’s always good to get a native speaker to proofread the translation before you use it in order to make sure there are no embarrassing mishaps. Taking the example of translating English to French again, you can ask French proofreader to take a look at the translation. This reader does not have to be proficient at English, they only have to tell you if it flows and reads naturally in French and if the language is grammatically correct.
In the case that it is not, you can take it up with the translation services in UK that you used or employ a new translator. It’s better to spend a lot of time ensuring that you get a good translation than to publish a poor translation. The poor translation will reflect badly on you more than it will on the actual translator, since you are the one making it public.