They'd be on separate circuits though wouldn't they? The underfloor heating has it's own 13amp FCU if it developed a fault it would be isolated there. The server gear has it's own separate 13amp FCU.
As for the faulty hoover thing, there's not much I could about that anyway, it appears 3-4 rooms are all on the same ring end circuit anyway, so if anyone plugs a faulty hoover into one of the sockets it'd trip everything off in all 4 rooms. Unfortunately the house is entirely solid brick so no easy plasterboard rewires on offer, but it's served us ok for 30+ years that way. The alternative would be running the server gear off trailing sockets, which in my mind is exactly the same as running an extension from a new FCU, except the 13amp fuse is now in the all unit rather than a plug you can see with sockets on the end. To keep the network gear running in outages I have them on a small UPS anyway too.