Our house is full-brick. Double-brick on the exterior walls and single-brick for every internal wall. It was built in 1979 (I guess they liked to do things properly then).
We've only ever had the opportunity once of adding new electrical items to the single-brick walls (like a heated towel rail, new light switch and powerpoint), when we were renovating as the electrican had to chase a huge chunk out of the wall, lay the cables, and then the hole was filled back up and painted over. That's a pretty major operation.
Is there any other way that we can add or modify the electrical items inside a single brick wall? We now want to run CAT5 and we've got all the external walls done, but not the internals.