I was referring to the Government's Code of practice dated 13 March 2003, which related only to public sector contracts. This Government abolished this on 23 March 2011.
This protected pension schemes for public sector workers.
My understanding of TUPE is that it did not protect private sector workers' pensions. But after a TUPE transfer they are usually entitled to expect a contribution of 6% from their employer.
The TUPE transfer should not affect your previously accumulated pension. My understanding of pensions is that there should be some consultation before changes are made. it sounds as if this may not have happened. I think you need to discuss this with thetrustees.
Are you a member of a union. They are usually expert in this area.
Personally, I would write to Jim Dowd our local MP for help.