Integrate with Campaign Monitor
Campaign Monitor is THE emarketing tool of choice. It is fast, efficient and offers extremely good value for money as you only pay for what you do...no monthly fees.
Hi there lfeatherby, you may want to check out a new integration, Imera (http://www.imeraapp.com). It's great for creating new invoices in Xero after a campaign has been sent in Campaign Monitor, so could be what you're looking for here.
OneSaas (http://www.onesaas.com) already integates Xero with Campaign Monitor.