Am interested to know how far back would one have been expected to
obtain Building Notices?

We've lived in an old Victorian house for 20+ years and in the first
5years installed a boiler, had rsj's put in where structural walls
needed removing, windows installed and have even had the roof
reinforced. All major works were designed/supervised by a qualified
Structural Engineer - but the Council were never involved; never heard
of these things before now. Is this likely to affect us being able to
sell the house - which we hope to do next year?