In a domestic situation it is highly unlikely to have a induction loop
system fitted.

I can assure you it is not. Many hearing aid users have modified telephones,
or induction loops for television watching within their homes. These devices
are cheap and widely available.

I think the term 'reasonable expectations' would apply to all
installations.

Indeed. I think it is unreasonable to install an unbalanced lighting system
that may have interference effects over a wide area, including your
neighbour's property, who may not be able to use their telephone or watch TV
and certainly are unable to go into your house to fix the circuit.

Christian.