"We had a chapel meeting on 10 April and in principle the members have accepted the final amended package," said East of England branch secretary Vernon Robson. "There's light at the end of the tunnel, and I hope this brings an end to it."
A paper ballot on the package will now be sent out to members, which Robson said would have to be concluded "very quickly".
Plant three will close, and a skeleton staff will remain in plant one, with plant two remaining open. In total, 380 jobs will be lost. The first 158 staff are due to leave on 8 May.
Original proposals had to be re-drawn after the firm sought a 2m cut in the budget for the deal to 6m. The deal also includes new working terms and conditions.
