I had the same issue when I worked for the NHS about 6 years ago. They wanted to put us on monthly pay instead of fortnightly. They were willing to give us 2 months notice which was not unreasonable but could never give us a definate date. Instead a lot of scaremongering (sp?) went on with rumors flying around about how we were currently in that 2 month period and the monthly pay would start next week.

I would see a union rep if you have one, UNISON were really good for us and may even offer you advice if you are not a member, perhaps for a small fee.

Hope you get it sorted