The Birds Eye site says that the vegetables are complimented with herbs & seasoning - if that's all then they'd be free. Check the ingredients on the pack and as long as there's no oil or any other syn'd ingredients, they'll deffo be free.
Update - I've just found the NV & ingredients on another site and it's apparently got butter and rice starch in the Green Medley one. You'd have to put the full NV through the SW calculator to get the final answer on the syn's per serving. The butter & starch could be negligible compared to the amount of veg but better check so you don't underestimate your potential syn intake.