So if you are rostered off on a bank holiday you also want a day off in lieu! Can't see that happening.
If you want a 4 day shift off you have to put in 5 days leave which will give you 4 rostered days off 4 work days off and 4 rostered days off, so for 5 days leave you get 12 days off, sounds bloody good to me!
The european working time directive states that employees are entitled to a minimum of 4 weeks annual leave per year. The problem comes when you are taking leave in hours rather than days, I am in dispute with my company at the moment who have changed the contract to read nnx7.5hrs instead of nndays (nn being the number of days). That way they have you if you work anything more than 7.5hrs a day. It looks like I'll shortly be given the ultimatum sign it or here's your notice (which believe it or not they can legally do).
Bank holidays are not statutory days off, it will be (should be specified) in your contract if they are or not. Many moons ago when I worked at a place that did 4x4 shifts we had the same amount of holiday days as day workers - 20 days, however as we worked 12hr days we had to put in 1.5 days for a single day off, however as we were on shift we were also given an extra 12 days leave to cover bank holidays (8x1.5) which seemed pretty fair to me.