There are a few data centers listed under "Kent" and much more under "London" at DataCenterMap. I would know suggest you which one to use. The only facility we know is TelecityGroup. We have our EU infrastructure hosted in one of their data centers and they are good. I would suggest you to try to work out a good deal on power as would add a lot to your bill. Other thing to consider is to check whether LINX is presented in any of the data centers you'd colocate with.
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