There is no escaping Brexit, even within Westlaw! There is now a section of draft statutory instruments (SIs) that relate to the leaving of the EU. This can be found under the Browse section of the legislation content screen:
There are quite a lot of them:
There is also a section headed 'Retained EU Legislation' which has selected EU documents appearing in a new format, and aims to preserve a snapshot of current EU legislation. Documents display as currently in force, with amendments pending (the exclamation mark).