resumeIn brief
The similarity of forms does not mean that the whole ensemble is from one era.
Useful to know
The Palace of Westminster has been rebuilt since 1840 in the neo-Gothic style on a site with significant medieval remains. The common site also includes the Abbey of Westminster and the Church of St. Margarita". [1]
When looking at the complex, specify which building shows the photo. A Gothic form may belong to a medieval construction or to a later interpretation. Instead of choosing one date for everything, compare the purpose, the construction stages, and the relationship between the buildings. Thus, the historical ensemble becomes more understandable than the general description "old English style".
Sources
For further detail and to check the information: