Is there a widget or interface for Payzone a barclays merchant account that will work with Infusionsoft by Keap
I have not heard of one directly. You can try contacting the following merchants to see if they support it.
Nexus Merchants - https://www.nexusmerchants.com/
Cart Connect - https://www.cartconnect.net/infusionsoft.cfm
Infusionsoft use to support SagePay, which could have supported Barclaycard. But this is no longer available for selection.