You are expected to work some bank holidays quite how they work it out is beyond me as I never had to work them because I had been there for a long time. Bank holiday work is now mainly on the phones and you are expected to work from home. They will tell you what hours are needed and what hours you will work.
Half half but the company is horrendous and I would rather not
Some do but it depends on where the job is as contract states you could work them
Bank holidays are quite easy to get off if requested.