HomePlug won't interfere with other domestic appliances. They are certified according to all essential CE standards, also according to the EMC emission and interference standards. Likewise, other domestic appliances sold within the EU have to be labelled with the CE emblem. This guarantees that they don't interfere with each other.
Your electric meter represents a natural barrier, however we recommend enabling encryption.
The frequencies used by the HomePlugs are in the range of 4MHz to 21MHz so they cannot interfere with UK radio reception.
The transmitting level used is very small and uses symmetrical phase coupling, so only a small part of this power will be radiated by the power grid. Consequently there is no interference in the amateur radio band either.