Not all the Russian translators in London might have websites to create their online presence.
Where else to search for them?
Firstly, try your luck on social media: Twitter, Facebook or LinkedIn.
I would highly recommend LinkedIn. It gives you options there to search for professionals locally, i.e. you can indicate which area. But mind, the best Russian translator services located in London might be expensive.
Secondly, try to search on freelancing platforms, like Upwork and Fiverr. There are a lot of freelance translators there. You will surely outsource the one you are looking for.
By the way, I also provide English to Russian translator services (plus some other languages), you are welcome to send me your enquiries!