The Vaccines are far more important than (preventative) panacur, so get the vaccines done straight away. Most vets will say it's fine to give panacur at the same time so I would continue with that as well. If the bun is considered frail then I would stop the panacur until afterwards but there's no real evidence it would be a problem. The main reason I wouldn't normally do them at the same time is Psychological, after the jabs the bun would be feeling a bit off so forcing them to take panacur isn't very nice.