I ask because there is the start of NEST & autoenrolment later this year in which your employer will have to be contributing to your pension. (4% of your salary I believe)

I think the OP already gets an employer contribution, which in all likelihood is better than the NEST proposal.

"my ongoing pension contribtions have to be paid into Aviva from now on"

If there was no employer contribution there'd be no need to stay in the employer's scheme.

Scott.