Long notice period or new role with no trial period?

Hi

I would greatly appreciate any help. Here is my situation:

The company I worked for was acquired by a bigger company and as a result there was a 90 day consultation period that finished on 5 Jan 2009. Their plan was to keep 30% of employees on permanent basis, keep 30% of employees on short term integration basis and make the rest redundant by 31 March 2009.

During the consultation period I was considered for a couple alternative positions which weren't suitable due to location. Another option was the integration role. During my final one to one I was told that I have scored enough points in the selection process to be kept on in an integration role for 15 months as a Software Developer.

This was followed by a letter stating:
"Further to your recent consultation meeting, I'm writing to confirm the arrangements relating to your Integration/Transition role.
As you know, following the acquisition of XXX, a substantial re-organisation has been implemented which has regrettably resulted in the redundancy of your role.
As discussed you will, however, be required to continue in your current role and assist in integration/transition activities until your role actually becomes redundant. It is anticipated that this will be no later than 31 March 2010, at which point your employment will terminate due to redundancy."

My new employer says that my contract doesn't change and I will stay on existing terms and conditions.

So this means in their eyes there is no "4 week trial" period.

I believe the integration offer constitutes a new role and I should have been given a trial period because:
- it's short term
- currently there is no work to do, but future work is likely to be different to my previous work
- I fit into the new organisation chart as a Software Developer, whereas my previous title was Software and Systems Engineer
- my payslip says I'm in a different department
- my manager is now 100 miles away
- anyone on an integration role is not invited to corporate events

My questions are:
Have I been essentially given 15 months notice period?
Can I "reject the new role" and claim redundancy now?

Thank you

I forgot to add that I have 4 years of continuous service.

Can anyone help?