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a harry potter-story ?

They moved the building by 11 houses? And (depending on numbering scheme) perhaps to the other side of the street?

Maybe they misunderstood the Gregorian calendar reform ?

This is part of the Phillimore Kensington estate.The late-Georgian terrace on the east side of Hornton Street was demolished in 1903 and the present terrace of a block of flats and 21 houses were built in its place with postal numbers 1-43 (odd) starting from Horton Place. In 1928 the terrace was renumbered 12-54 (even) with the new numbering starting with premises to the south of Horton Place.

Thanks, how extremely informative!

Thank you for the information.
Nevertheless nice to use the same number style again. :-)