Power supply boiler circuit

Hello,
I just want to double check the wiring on a supply for heating-(oil)boiler. If I wire it up in such a way that the call for heat using switched mains power at two points in the circuit, does it constitute bridging or some other problem? or is it like on a ring circuit where the current can flow from two directions?
The supply is in a radial lighting circuit and the other point is underfloor heating control in another room

Very simplified diagram of mains supply:
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You can't take the supply from two different circuits that would be very dangerous.
It should be supplied via a 3A fused spur and preferably off a ring main.

Your diagram doesn't make a lot of sense to be, but what you seem to be asking is "Can I run the UFH control off a separate circuit to the boiler supply?". If the UFH boiler demand contacts are volt free then yes, you can, as long as the live supply and switch live return to these contacts comes from the boiler.

However, if the controls simply give out a switched live to demand heat, you will need to use a contactor or relay as a means to isolate the two circuits from each other.

I think I did not draw the diagram clearly enough. It is the same circuit but the point where there is a spur feeding the UFH is away from the point where there is a spur feeding the boiler. The boiler interlock coming from the UFH control goes back carrying 230v supply but it is connected to a relay in the UFH wiring box thus:
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