Does a Banksman Need to Be Ipaf Trained?

IPAF is not a legal requirement. Just an accredited body that most big sites or contractors insist on. Suitable and sufficient training will suffice. As for a passenger, no, they wouldn't require IPAF unless again, site rules specified differently.

Is IPAF training a legal requirement?

There is no specific legal requirement for an employee working at height to have IPAF training certification.

Can untrained operators legally operate MEWPs?

Never allow an untrained or unauthorised person to operate the MEWP. Operation of the MEWP is your responsibility.