[DanaC]

If not part of Schengen, then why will all Schengen rules, that make British travel easy in the EU, now be removed? Because Britain was part of (but did not fully implement) Schengen

No. Sorry but you are wrong.

The Schengen Agreement and its implementing Convention were enacted in 1995 only for some signatories,but just over two years later during the Amsterdam Intergovernmental Conference, all European Union member states except the United Kingdom and Ireland had signed the Agreement. It was during those negotiations, which led to the Amsterdam Treaty, that the incorporation of the Schengen acquis[7] into the main body of European Union law was agreed along with opt-outs for Ireland and the United Kingdom, which were to remain outside of the Schengen Area.[8]